In this episode of the Epigenetics Podcast, we talked with Yadira Soto-Feliciano from MIT about her work on the Menin-MLL complex and the effect of small molecules on its stability in leukemia. We explore the pivotal moments that led her to cancer biology during her graduate studies, where her work included ground-breaking research on the role of the plant homeodomain Finger protein-6 (PHF-6) in leukemia. This work bridged the realms of chromatin accessibility, transcription factors, and cancer cell lineage, providing critical evidence for the concept of lineage plasticity in cancer biology—a topic that has gained significant traction in recent years. Dr. Soto-Feliciano discusses how advances in techniques like CRISPR and ChIP-sequencing have shaped her research, enabling deeper insights into the mechanisms underlying cancer cell identity. As our discussion transitions, Dr. Soto-Feliciano shares her experience in David Allis's lab, illustrating how the collaboration across diverse scientific disciplines enhanced her understanding of chromatin biology and generated significant insights into the mechanics of epigenetic regulation. Highlighting a recent 2023 publication, we unpack her findings related to the conserved molecular switch between MLL1 and MLL3 complexes. These discoveries revealed how the application of small-molecule inhibitors of the menin-MLL interaction can alter gene expression and affect leukemia cells’ responses to treatments. We also touch on the operational dynamics within her lab at MIT, established during challenging times marked by the pandemic. Yadira is dedicated to fostering a collaborative and respectful environment among her team, comprised of PhD candidates and research technicians, all sharing a commitment to unraveling the complexities of chromatin regulation. She emphasizes the significance of understanding chromatin scaffold proteins and their role in regulating gene expression and genome organization. References Soto-Feliciano, Y. M., Bartlebaugh, J. M. E., Liu, Y., Sánchez-Rivera, F. J., Bhutkar, A., Weintraub, A. S., Buenrostro, J. D., Cheng, C. S., Regev, A., Jacks, T. E., Young, R. A., & Hemann, M. T. (2017). PHF6 regulates phenotypic plasticity through chromatin organization within lineage-specific genes. Genes & development, 31(10), 973–989. https://doi.org/10.1101/gad.295857.117 Soto-Feliciano, Y. M., Sánchez-Rivera, F. J., Perner, F., Barrows, D. W., Kastenhuber, E. R., Ho, Y. J., Carroll, T., Xiong, Y., Anand, D., Soshnev, A. A., Gates, L., Beytagh, M. C., Cheon, D., Gu, S., Liu, X. S., Krivtsov, A. V., Meneses, M., de Stanchina, E., Stone, R. M., Armstrong, S. A., … Allis, C. D. (2023). A Molecular Switch between Mammalian MLL Complexes Dictates Response to Menin-MLL Inhibition. Cancer discovery, 13(1), 146–169. https://doi.org/10.1158/2159-8290.CD-22-0416 Zhu, C., Soto-Feliciano, Y. M., Morris, J. P., Huang, C. H., Koche, R. P., Ho, Y. J., Banito, A., Chen, C. W., Shroff, A., Tian, S., Livshits, G., Chen, C. C., Fennell, M., Armstrong, S. A., Allis, C. D., Tschaharganeh, D. F., & Lowe, S. W. (2023). MLL3 regulates the CDKN2A tumor suppressor locus in liver cancer. eLife, 12, e80854. https://doi.org/10.7554/eLife.80854 Related Episodes MLL Proteins in Mixed-Lineage Leukemia (Yali Dou) Targeting COMPASS to Cure Childhood Leukemia (Ali Shilatifard) Contact Epigenetics Podcast on Instagram Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Dr. Stefan Dillinger on LinkedIn Active Motif on LinkedIn Active Motif on Bluesky Email: podcast@activemotif.com
In this episode of the Epigenetics Podcast, we talked with Mary Anne Jelinek Associate Director of R&D at Active Motif about writing and reviewing grants in academia and industry. Learn from Dr. Jelinek’s years of experience writing and reviewing grants and get her best advice and insight for success. Hear about similarities and differences in preparing grants in academia vs. biotech or other industry settings. Key insights include: Finding Grant opportunities that exist for different sectors and countries, from the familiar ones like NIH and NSF in the United States grant funding offered by NATO for member countries. Learn about grants targeted to small businesses and specific allocation of resources intended to foster and promote innovation and entrepreneurship and how to navigate confidentiality when writing grants in industry, being mindful of conflict of interest and best practices. Coming up with ideas is easy – but how do you find institutes interested in funding those research areas? Get tips on how to submit a 1-page inquiry for feedback and guidance at early stages that will help your grant be robust and successful. Think you can go from idea to funding in 4 weeks? She has and discusses the best strategy to do this - collaboration is key and you’ll learn why. Get tips on wording and writing for reviewers who may not be experts in your field and how to “paint a picture” that makes it both clear and persuasive, including your writing style and use of diagrams and figures for those complex concepts. Hear all of Dr. Jelinek’s “best advice” and encouragement for dealing with stress and frustration that can be part of the process. Finally, as a co-developer for the first commercially available ChIP Kit, Dr. Jelinek tells the story of how this assay developed and became a gold-standard method for epigenetics. Tune in to this in depth and very helpful episode! Contact Epigenetics Podcast on X Epigenetics Podcast on Instagram Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Epigenetics Podcast on Threads Active Motif on X Active Motif on LinkedIn Email: podcast@activemotif.com
In this episode of the Epigenetics Podcast, we talked with Carl Wu from John's Hopkins University about his work on nucleosome remodeling, histone variants, and the role of single-molecule imaging in gene regulation. Our discussion starts with Carl Wu sharing his first significant milestones, a paper in "Cell" and the serendipitous discovery of DNA hypersensitive sites, which transformed our understanding of chromatin accessibility and its implications for gene regulation. As we delve into Dr. Wu’s specific areas of research, he elaborates on the biochemistry of nucleosome remodeling and the intricate role of chromatin remodeling enzymes like NURF. We discuss how these enzymes employ ATP hydrolysis to reposition nucleosomes, making DNA accessible for transcription. He then explains the collaborative relationship between chromatin remodelers and transcription factors, showcasing the fascinating interplay that governs gene expression and regulatory mechanisms. The conversation takes a deeper turn as we explore Carl Wu’s groundbreaking studies on histone variants, particularly H2AZ. He elucidates the role of SWR1 in facilitating the exchange between H2A and H2AZ in nucleosome arrays. The high-resolution structural insights garnered from recent studies reveal how the enzyme mediates histone eviction and insertion with remarkable precision, providing a clearer picture of chromatin dynamics at a molecular level. References Wu, C., Bingham, P. M., Livak, K. J., Holmgren, R., & Elgin, S. C. (1979). The chromatin structure of specific genes: I. Evidence for higher order domains of defined DNA sequence. Cell, 16(4), 797–806. https://doi.org/10.1016/0092-8674(79)90095-3 Wu, C., Wong, Y. C., & Elgin, S. C. (1979). The chromatin structure of specific genes: II. Disruption of chromatin structure during gene activity. Cell, 16(4), 807–814. https://doi.org/10.1016/0092-8674(79)90096-5 Wu C. (1980). The 5' ends of Drosophila heat shock genes in chromatin are hypersensitive to DNase I. Nature, 286(5776), 854–860. https://doi.org/10.1038/286854a0 Wu, C., Wilson, S., Walker, B., Dawid, I., Paisley, T., Zimarino, V., & Ueda, H. (1987). Purification and properties of Drosophila heat shock activator protein. Science (New York, N.Y.), 238(4831), 1247–1253. https://doi.org/10.1126/science.3685975 Mizuguchi, G., Shen, X., Landry, J., Wu, W. H., Sen, S., & Wu, C. (2004). ATP-driven exchange of histone H2AZ variant catalyzed by SWR1 chromatin remodeling complex. Science (New York, N.Y.), 303(5656), 343–348. https://doi.org/10.1126/science.1090701 Kim, J. M., Visanpattanasin, P., Jou, V., Liu, S., Tang, X., Zheng, Q., Li, K. Y., Snedeker, J., Lavis, L. D., Lionnet, T., & Wu, C. (2021). Single-molecule imaging of chromatin remodelers reveals role of ATPase in promoting fast kinetics of target search and dissociation from chromatin. eLife, 10, e69387. https://doi.org/10.7554/eLife.69387 Related Episodes Multiple challenges of ATAC-Seq, Points to Consider (Yuan Xue) Pioneer Transcription Factors and Their Influence on Chromatin Structure (Ken Zaret) ATAC-Seq, scATAC-Seq and Chromatin Dynamics in Single-Cells (Jason Buenrostro) Contact Epigenetics Podcast on X Epigenetics Podcast on Instagram Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Epigenetics Podcast on Threads Active Motif on X Active Motif on LinkedIn Email: podcast@activemotif.com
In this episode of the Epigenetics Podcast, we talked with Mitinori Saitou from Kyoto University about his work on germ cell development, focusing on proteins like BLIMP1 and PRDM14, reprogramming iPSCs, and his vision to address infertility and genetic disorders through epigenetic insights. To start our discussion, Dr. Saitou shares the foundation of his research, which centers on the mechanisms of germ cell development across various species, including mice, non-human primates, and humans. He provides insight into his early work examining the roles of two key proteins: BLIMP1 and PRDM14. These proteins are essential for germline specification in mammals, and their functions are unveiled through detailed exploration of knockout models. In particular, Dr. Saitou elucidates the critical events in germ cell specification, highlighting how disruptions to the functions of these proteins lead to significant impairments in development. As the conversation deepens, we discuss Dr. Saitou’s groundbreaking advances in human-induced pluripotent stem cells (iPSCs). He elaborates on the processes involved in reprogramming these cells to form primordial germ cell-like cells, emphasizing the significance of understanding various cellular contexts and transcriptional regulation. Dr. Saitou then details how overexpression of certain factors in embryonic stem cells can induce these germline characteristics, presenting the promise of innovation in regenerative medicine and reproductive biology. We end our talk with the exploration of chromatin remodeling that occurs during germ cell development, including fascinating details about DNA and histone modification dynamics. Dr. Saitou articulates how the epigenetic landscape shifts during the transition from pluripotent states to germ cell specification, providing a detailed comparison between mouse and human systems. This highlights the complexity of gene regulation and the importance of specific epigenetic markers in establishing and maintaining cellular identity. References Yamaji, M., Seki, Y., Kurimoto, K. et al. Critical function of Prdm14 for the establishment of the germ cell lineage in mice. Nat Genet 40, 1016–1022 (2008). https://doi.org/10.1038/ng.186 Katsuhiko Hayashi et al., Offspring from Oocytes Derived from in Vitro Primordial Germ Cell–like Cells in Mice. Science 338, 971-975 (2012). DOI: 10.1126/science.1226889 Nakaki, F., Hayashi, K., Ohta, H. et al. Induction of mouse germ-cell fate by transcription factors in vitro. Nature 501, 222–226 (2013). https://doi.org/10.1038/nature12417 Nakamura, T., Okamoto, I., Sasaki, K. et al. A developmental coordinate of pluripotency among mice, monkeys and humans. Nature 537, 57–62 (2016). https://doi.org/10.1038/nature19096 Murase, Y., Yokogawa, R., Yabuta, Y. et al. In vitro reconstitution of epigenetic reprogramming in the human germ line. Nature 631, 170–178 (2024). https://doi.org/10.1038/s41586-024-07526-6 Contact Epigenetics Podcast on X Epigenetics Podcast on Instagram Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Epigenetics Podcast on Threads Active Motif on X Active Motif on LinkedIn Email: podcast@activemotif.com
In this episode of the Epigenetics Podcast, we talked with Karine Le Roch from the University of California at Riverside about her work on malaria chromatin structure and its transcriptional regulation. In this Interview Dr. Le Roch discusses her investigation of post-transcriptional controls and nucleosome positioning in Plasmodium falciparum, employing next-generation sequencing and chromatin profiling methods. Karin emphasizes how these methodologies contribute to a comprehensive understanding of gene regulation beyond mere transcription initiation, emphasizing the significance of mRNA binding proteins and their role in stabilizing gene transcripts for translation. This exploration of the interaction between chromatin structure, transcriptional dynamics, and post-transcriptional regulation reveals a multidimensional perspective of gene expression. Transitioning to her lab’s focus on high-throughput genomic technologies, we discuss how Karin and her team are uncovering conserved and species-specific genomic organization principles within various Plasmodium species. By generating 3D genomic models through Hi-C experiments, she describes how they have identified patterns that underline the parasite's immune evasion strategies. In particular, we learn how genes involved in antigenic variation are controlled through intricate epigenetic mechanisms, illuminating the pathways that allow these parasites to elude host immune responses. References Le Roch, K. G., Zhou, Y., Blair, P. L., Grainger, M., Moch, J. K., Haynes, J. D., De La Vega, P., Holder, A. A., Batalov, S., Carucci, D. J., & Winzeler, E. A. (2003). Discovery of gene function by expression profiling of the malaria parasite life cycle. Science (New York, N.Y.), 301(5639), 1503–1508. https://doi.org/10.1126/science.1087025 Ponts, N., Harris, E. Y., Prudhomme, J., Wick, I., Eckhardt-Ludka, C., Hicks, G. R., Hardiman, G., Lonardi, S., & Le Roch, K. G. (2010). Nucleosome landscape and control of transcription in the human malaria parasite. Genome research, 20(2), 228–238. https://doi.org/10.1101/gr.101063.109 Bunnik, E. M., Cook, K. B., Varoquaux, N., Batugedara, G., Prudhomme, J., Cort, A., Shi, L., Andolina, C., Ross, L. S., Brady, D., Fidock, D. A., Nosten, F., Tewari, R., Sinnis, P., Ay, F., Vert, J. P., Noble, W. S., & Le Roch, K. G. (2018). Changes in genome organization of parasite-specific gene families during the Plasmodium transmission stages. Nature communications, 9(1), 1910. https://doi.org/10.1038/s41467-018-04295-5 Related Episodes Epigenetics in Human Malaria Parasites (Elena Gómez-Diaz) Contact Epigenetics Podcast on X Epigenetics Podcast on Instagram Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Epigenetics Podcast on Threads Active Motif on X Active Motif on LinkedIn Email: podcast@activemotif.com
In this episode of the Epigenetics Podcast, we talked with Bas van Steensel from the Netherlands Cancer Institute about his work on characterizing chromatin at the Nuclear Lamina. The Interview starts with discussing Bas van Steensel's significant contributions to understanding genome-nuclear lamina interactions. Bas detailed the development of the DAM-ID technique during his postdoctoral studies, which provided a novel way to map genome-wide occupancy and identify Lamina-Associated Domains (LADs). He elaborated on how LADs reveal a distinct domain architecture, often correlating with gene expression levels. This prompted an exploration of the dynamics of these domains during differentiation processes, allowing insights into how gene activation and repression are influenced by their positioning relative to the nuclear lamina. The conversation highlighted the intricate relationship between chromatin dynamics and gene regulation, with Bas sharing compelling findings on how LADs behave during cell differentiation. The research indicated that regions moving away from the lamina often correlated with increased gene expression, revealing a complex interplay of spatial genome organization and transcriptional activity. Additionally, we ventured into the significance of outreach and transparency in scientific research. Bas shared his philosophy regarding collaboration and the ethical responsibility of scientists to share knowledge and resources openly. He emphasized that making lab notebooks and research processes accessible can greatly enhance reproducibility and understanding in the scientific community. References Open Science Policy of our lab Guelen, L., Pagie, L., Brasset, E., Meuleman, W., Faza, M. B., Talhout, W., Eussen, B. H., de Klein, A., Wessels, L., de Laat, W., & van Steensel, B. (2008). Domain organization of human chromosomes revealed by mapping of nuclear lamina interactions. Nature, 453(7197), 948–951. https://doi.org/10.1038/nature06947 Kind, J., Pagie, L., Ortabozkoyun, H., Boyle, S., de Vries, S. S., Janssen, H., Amendola, M., Nolen, L. D., Bickmore, W. A., & van Steensel, B. (2013). Single-cell dynamics of genome-nuclear lamina interactions. Cell, 153(1), 178–192. https://doi.org/10.1016/j.cell.2013.02.028 Kind, J., Pagie, L., de Vries, S. S., Nahidiazar, L., Dey, S. S., Bienko, M., Zhan, Y., Lajoie, B., de Graaf, C. A., Amendola, M., Fudenberg, G., Imakaev, M., Mirny, L. A., Jalink, K., Dekker, J., van Oudenaarden, A., & van Steensel, B. (2015). Genome-wide maps of nuclear lamina interactions in single human cells. Cell, 163(1), 134–147. https://doi.org/10.1016/j.cell.2015.08.040 Leemans, C., van der Zwalm, M. C. H., Brueckner, L., Comoglio, F., van Schaik, T., Pagie, L., van Arensbergen, J., & van Steensel, B. (2019). Promoter-Intrinsic and Local Chromatin Features Determine Gene Repression in LADs. Cell, 177(4), 852–864.e14. https://doi.org/10.1016/j.cell.2019.03.009 van Schaik, T., Liu, N. Q., Manzo, S. G., Peric-Hupkes, D., de Wit, E., & van Steensel, B. (2022). CTCF and cohesin promote focal detachment of DNA from the nuclear lamina. Genome biology, 23(1), 185. https://doi.org/10.1186/s13059-022-02754-3 van Steensel B. (2018). Scientific honesty and publicly shared lab notebooks: Sharing lab notebooks along with publication would increase transparency and help to improve honesty when reporting results. EMBO reports, 19(10), e46866. https://doi.org/10.15252/embr.201846866 Related Episodes scDamID, EpiDamID and Lamina Associated Domains (Jop Kind) Identification of Functional Elements in the Genome (Bing Ren) Chromatin Profiling: From ChIP to CUT&RUN, CUT&Tag and CUTAC (Steven Henikoff) Contact Epigenetics Podcast on X Epigenetics Podcast on Instagram Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Epigenetics Podcast on Threads Active Motif on X Active Motif on LinkedIn Email: podcast@activemotif.com
In this episode of the Epigenetics Podcast, we caught up with Vladimir Teif from the University of Essex to talk about his work on nucleosome positioning in development and disease. Vladimir's research has been pivotal in understanding nucleosome positioning and its implications for cell differentiation, particularly in embryonic stem cells and cancer. We discuss his groundbreaking studies that first mapped nucleosome positions in various cell types and how these findings led to uncovering the intricate relationships between nucleosome stability, transcription factors, and DNA modifications such as methylation. This understanding has immense significance for cancer diagnostics, where knowing the spatial arrangement of nucleosomes could influence how aggressive a cancer type might be, or how a patient might respond to treatment. Transitioning from foundational research to clinical applications, Vladimir elaborates on his exciting work with liquid biopsies. By analyzing cell-free DNA from blood plasma, researchers can infer the nucleosome positioning and, ultimately, the presence of cancer without the need for invasive tissue biopsies. We explore how this new approach holds potential for earlier detection of cancers and more effective patient stratification, demonstrating a profound shift in how we leverage epigenetic data in clinical settings. References Vladimir B. Teif, Karsten Rippe, Predicting nucleosome positions on the DNA: combining intrinsic sequence preferences and remodeler activities, Nucleic Acids Research, Volume 37, Issue 17, 1 September 2009, Pages 5641–5655, https://doi.org/10.1093/nar/gkp610 Teif, V., Vainshtein, Y., Caudron-Herger, M. et al. Genome-wide nucleosome positioning during embryonic stem cell development. Nat Struct Mol Biol 19, 1185–1192 (2012). https://doi.org/10.1038/nsmb.2419 Beshnova DA, Cherstvy AG, Vainshtein Y, Teif VB (2014) Regulation of the Nucleosome Repeat Length In Vivo by the DNA Sequence, Protein Concentrations and Long-Range Interactions. PLoS Comput Biol 10(7): e1003698. https://doi.org/10.1371/journal.pcbi.1003698 Shtumpf, M., Piroeva, K.V., Agrawal, S.P. et al. NucPosDB: a database of nucleosome positioning in vivo and nucleosomics of cell-free DNA. Chromosoma 131, 19–28 (2022). https://doi.org/10.1007/s00412-021-00766-9 Related Episodes Circulating Epigenetic Biomarkers in Cancer (Charlotte Proudhon) Epigenome-based Precision Medicine (Eleni Tomazou) Contact Epigenetics Podcast on X Epigenetics Podcast on Instagram Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Epigenetics Podcast on Threads Active Motif on X Active Motif on LinkedIn Email: podcast@activemotif.com
In this episode of the Epigenetics Podcast, we talked with Johnathan Whetstine from Fox Chase Cancer Center about his work on how histone demethylases affect gene expression and cancer cell stability. The Interview start by discussing a pivotal paper from Jonathan's lab in 2010, where they identified a role for the KDM4A histone demethylase in replication timing and cell cycle progression. They elaborate on the discoveries made regarding the link between histone marks, replication timing, and gene expression control. Jonathan explains the impact of microRNAs on regulating KDM4A and how protein turnover rates can influence cellular responses to treatments like mTOR inhibitors. Further, they explore the causal relationship between histone marks and replication timing, demonstrating how alterations in epigenetic regulation can affect genome stability. Jonathan shares insights from his latest research on H3K9 methylation balance at the MLL-KM2A locus, elucidating how these epigenetic modifications regulate amplifications and rearrangements in cancer cells. The episode concludes with a discussion on the establishment of the Cancer Epigenetics Institute at Fox Chase Cancer Center, aiming to bridge academia and industry to accelerate translational research in cancer epigenetics. References Black, J. C., Allen, A., Van Rechem, C., Forbes, E., Longworth, M., Tschöp, K., Rinehart, C., Quiton, J., Walsh, R., Smallwood, A., Dyson, N. J., & Whetstine, J. R. (2010). Conserved antagonism between JMJD2A/KDM4A and HP1γ during cell cycle progression. Molecular cell, 40(5), 736–748. https://doi.org/10.1016/j.molcel.2010.11.008 Mishra, S., Van Rechem, C., Pal, S., Clarke, T. L., Chakraborty, D., Mahan, S. D., Black, J. C., Murphy, S. E., Lawrence, M. S., Daniels, D. L., & Whetstine, J. R. (2018). Cross-talk between Lysine-Modifying Enzymes Controls Site-Specific DNA Amplifications. Cell, 174(4), 803–817.e16. https://doi.org/10.1016/j.cell.2018.06.018 Van Rechem, C., Ji, F., Chakraborty, D., Black, J. C., Sadreyev, R. I., & Whetstine, J. R. (2021). Collective regulation of chromatin modifications predicts replication timing during cell cycle. Cell reports, 37(1), 109799. https://doi.org/10.1016/j.celrep.2021.109799 Gray, Z. H., Chakraborty, D., Duttweiler, R. R., Alekbaeva, G. D., Murphy, S. E., Chetal, K., Ji, F., Ferman, B. I., Honer, M. A., Wang, Z., Myers, C., Sun, R., Kaniskan, H. Ü., Toma, M. M., Bondarenko, E. A., Santoro, J. N., Miranda, C., Dillingham, M. E., Tang, R., Gozani, O., … Whetstine, J. R. (2023). Epigenetic balance ensures mechanistic control of MLL amplification and rearrangement. Cell, 186(21), 4528–4545.e18. https://doi.org/10.1016/j.cell.2023.09.009 Related Episodes The Impact of Chromatin Modifiers on Disease Development and Progression (Capucine van Rechem) Contact Epigenetics Podcast on X Epigenetics Podcast on Instagram Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Epigenetics Podcast on Threads Active Motif on X Active Motif on LinkedIn Email: podcast@activemotif.com
In this episode of the Epigenetics Podcast, we talked with Christa Buecker from the Max Perutz Laboratories in Vienna about her work on transcriptional regulation during early embryonic development. Dr. Buecker unravels the differences between naive and primed pluripotency states, showcasing how OCT4 relocalization and enhancer chromatin landscapes play pivotal roles during this transition. The conversation delves into the intricate interplay of transcription factors like OCT4 and OTX2, shedding light on their collaborative efforts in regulating gene expression during differentiation. Dr. Buecker then shares insights from her study on enhancer elements controlling FGF5 expression and discusses the surprising revelation that individual enhancers show no intrinsic activity but work together in a super additive fashion. She also touches upon her research on IRF1's connection to the gene regulatory network and its role in protecting cells against viral infections. The conversation shifts to Dr. Buecker's current research endeavors, focusing on exploring the strength of enhancers and their impact on gene expression at different distances from promoters. She shares her vision for future experiments and the integration of enhancers to decipher their impact on transcription regulation. References Buecker, C., Srinivasan, R., Wu, Z., Calo, E., Acampora, D., Faial, T., Simeone, A., Tan, M., Swigut, T., & Wysocka, J. (2014). Reorganization of enhancer patterns in transition from naive to primed pluripotency. Cell stem cell, 14(6), 838–853. https://doi.org/10.1016/j.stem.2014.04.003 Thomas, H. F., Kotova, E., Jayaram, S., Pilz, A., Romeike, M., Lackner, A., Penz, T., Bock, C., Leeb, M., Halbritter, F., Wysocka, J., & Buecker, C. (2021). Temporal dissection of an enhancer cluster reveals distinct temporal and functional contributions of individual elements. Molecular cell, 81(5), 969–982.e13. https://doi.org/10.1016/j.molcel.2020.12.047 Romeike, M., Spach, S., Huber, M., Feng, S., Vainorius, G., Elling, U., Versteeg, G. A., & Buecker, C. (2022). Transient upregulation of IRF1 during exit from naive pluripotency confers viral protection. EMBO reports, 23(9), e55375. https://doi.org/10.15252/embr.202255375 Related Episodes Enhancer Communities in Adipocyte Differentiation (Susanne Mandrup) Enhancer-Promoter Interactions During Development (Yad Ghavi-Helm) Enhancers and Chromatin Remodeling in Mammary Gland Development (Camila dos Santos) Ultraconserved Enhancers and Enhancer Redundancy (Diane Dickel) Contact Epigenetics Podcast on X Epigenetics Podcast on Instagram Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Epigenetics Podcast on Threads Active Motif on X Active Motif on LinkedIn Email: podcast@activemotif.com
In this episode of the Epigenetics Podcast, we talked with Claire Rougeulle from the Epigenetics and Cell Fate Center at Université Paris City about her work on gene expression control, the intricacies of X-chromosome inactivation, and the potential of non-coding RNAs in this process. In this episode Claire Rougeulle explains her discoveries regarding the transcription regulation of XIST by factors like YY1 and the erosion of X-chromosome inactivation in human pluripotent stem cells. She shares the complexity of distinguishing between epigenetics and transcriptional regulation, highlighting the challenges in studying allelic expression of X-chromosomes at the single-cell level. The Episode further explores Claire's findings on the XACT locus regulation, evolution from retroviruses, and its potential role in preventing X-chromosome silencing. Claire also shares her future research focus on understanding X-inactivation establishment in humans and the transition from XIST attenuating to silencing X-chromosomes after implantation. References Makhlouf, M., Ouimette, J. F., Oldfield, A., Navarro, P., Neuillet, D., & Rougeulle, C. (2014). A prominent and conserved role for YY1 in Xist transcriptional activation. Nature communications, 5, 4878. https://doi.org/10.1038/ncomms5878 Vallot, C., Ouimette, J. F., Makhlouf, M., Féraud, O., Pontis, J., Côme, J., Martinat, C., Bennaceur-Griscelli, A., Lalande, M., & Rougeulle, C. (2015). Erosion of X Chromosome Inactivation in Human Pluripotent Cells Initiates with XACT Coating and Depends on a Specific Heterochromatin Landscape. Cell stem cell, 16(5), 533–546. https://doi.org/10.1016/j.stem.2015.03.016 Casanova, M., Moscatelli, M., Chauvière, L. É., Huret, C., Samson, J., Liyakat Ali, T. M., Rosspopoff, O., & Rougeulle, C. (2019). A primate-specific retroviral enhancer wires the XACT lncRNA into the core pluripotency network in humans. Nature communications, 10(1), 5652. https://doi.org/10.1038/s41467-019-13551-1 Related Episodes Epigenetics and X-Inactivation (Edith Heard) Investigating the Dynamics of Epigenetic Plasticity in Cancer with Single Cell Technologies (Céline Vallot) Contact Epigenetics Podcast on X Epigenetics Podcast on Instagram Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Epigenetics Podcast on Threads Active Motif on X Active Motif on LinkedIn Email: podcast@activemotif.com
In this episode of the Epigenetics Podcast, we talked with James Hackett from the EMBL in Rome about his work on epigenetic mechanisms in genome regulation and developmental programming. One of James Hackett's significant studies focused on DNA methylation and genome defense mechanisms in the germline, exploring the role of chromatin modifications in mammalian gene regulation. He delves into investigating the erasure of DNA methylation in the germline, highlighting the key role of the TET-enzymes in demethylation processes. Dr. Hackett shares insights from his research on pluripotent stem cells, where he mapped genome-wide DNA methylation and hydroxymethylation in different pluripotent states. He discusses the impact of extrinsic conditions on pluripotent states and the biases observed in lineage preferences. Furthermore, the discussion delves into the development of a CRISPR screening tool to study cell fate transitions, particularly focusing on the genetic factors contributing to germline specification. He also talks about his work on epigenetic inheritance, highlighting the importance of precise perturbations in understanding chromatin modifications and their functional implications. In a recent study, the Hackett lab focuses on systematic epigenome editing to investigate the context-dependent functions of chromatin modifications. We hear about this work, and the complexity of interactions between chromatin marks, DNA sequences, and transcription factors, shedding light on the nuanced effects of various chromatin modifications on gene expression. References Hackett JA, Reddington JP, Nestor CE, et al. Promoter DNA methylation couples genome-defence mechanisms to epigenetic reprogramming in the mouse germline. Development (Cambridge, England). 2012 Oct;139(19):3623-3632. DOI: 10.1242/dev.081661. PMID: 22949617; PMCID: PMC3436114. Hackett JA, Sengupta R, Zylicz JJ, et al. Germline DNA demethylation dynamics and imprint erasure through 5-hydroxymethylcytosine. Science (New York, N.Y.). 2013 Jan;339(6118):448-452. DOI: 10.1126/science.1229277. PMID: 23223451; PMCID: PMC3847602. Hackett JA, Kobayashi T, Dietmann S, Surani MA. Activation of Lineage Regulators and Transposable Elements across a Pluripotent Spectrum. Stem Cell Reports. 2017 Jun;8(6):1645-1658. DOI: 10.1016/j.stemcr.2017.05.014. PMID: 28591649; PMCID: PMC5470235. Hackett JA, Huang Y, Günesdogan U, et al. Tracing the transitions from pluripotency to germ cell fate with CRISPR screening. Nature Communications. 2018 Oct;9(1):4292. DOI: 10.1038/s41467-018-06230-0. PMID: 30327475; PMCID: PMC6191455. Related Episodes Epigenetic and Metabolic Regulation of Early Development (Jan Żylicz) H3K79 Methylation, DOT1L, and FOXG1 in Neural Development (Tanja Vogel) The Impact of Chromatin Modifiers on Disease Development and Progression (Capucine van Rechem) Contact Epigenetics Podcast on X Epigenetics Podcast on Instagram Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Epigenetics Podcast on Threads Active Motif on X Active Motif on LinkedIn Email: podcast@activemotif.com
In this episode of the Epigenetics Podcast, we talked with Lothar Schermelleh from the University of Oxford about his work on advanced optical imaging in 3D nuclear organisation. The interview starts by Lothar Schermelleh sharing his groundbreaking work in understanding chromatin organization using super-resolution microscopy techniques. He then delves into his past experiments, including his publication on imaging chromatin domains and X chromosome inactivation. His work showcases the power of structured illumination microscopy in overcoming diffraction limits, revealing insights into nuclear organization and regulation. Lothar also discusses refining methods for labeling chromosome territories and replication domains, as well as exploring structural and functional nuclear organization using advanced microscopy techniques. They touch on the potential of AI in microscopy, the importance of quality control in imaging, and Lothar's grant proposal for developing artifact-free, super-resolution imaging under cryo conditions with adaptive optics. The conversation emphasizes the intersection of technology development and biological applications, highlighting the importance of addressing specific biological questions through innovative imaging approaches. References Schermelleh, L., Carlton, P. M., Haase, S., Shao, L., Winoto, L., Kner, P., Burke, B., Cardoso, M. C., Agard, D. A., Gustafsson, M. G., Leonhardt, H., & Sedat, J. W. (2008). Subdiffraction multicolor imaging of the nuclear periphery with 3D structured illumination microscopy. Science (New York, N.Y.), 320(5881), 1332–1336. https://doi.org/10.1126/science.1156947 Schermelleh, L., Heintzmann, R., & Leonhardt, H. (2010). A guide to super-resolution fluorescence microscopy. The Journal of cell biology, 190(2), 165–175. https://doi.org/10.1083/jcb.201002018 Smeets, D., Markaki, Y., Schmid, V. J., Kraus, F., Tattermusch, A., Cerase, A., Sterr, M., Fiedler, S., Demmerle, J., Popken, J., Leonhardt, H., Brockdorff, N., Cremer, T., Schermelleh, L., & Cremer, M. (2014). Three-dimensional super-resolution microscopy of the inactive X chromosome territory reveals a collapse of its active nuclear compartment harboring distinct Xist RNA foci. Epigenetics & chromatin, 7, 8. https://doi.org/10.1186/1756-8935-7-8 Ball, G., Demmerle, J., Kaufmann, R., Davis, I., Dobbie, I. M., & Schermelleh, L. (2015). SIMcheck: a Toolbox for Successful Super-resolution Structured Illumination Microscopy. Scientific reports, 5, 15915. https://doi.org/10.1038/srep15915 Related Episodes Long-Range Transcriptional Control by 3D Chromosome Structure (Luca Giorgetti) Analysis of 3D Chromatin Structure Using Super-Resolution Imaging (Alistair Boettiger) Contact Epigenetics Podcast on X Epigenetics Podcast on Instagram Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Epigenetics Podcast on Threads Active Motif on X Active Motif on LinkedIn Email: podcast@activemotif.com
In this episode of the Epigenetics Podcast, we talked with Dr. Stephan Hamperl from the Helmholtz Zentrum Munich about his work on how conflicts between transcription, replication, and R-loop formation influence genome stability in human cells. During the early stages of his career Stephan studied conflicts between transcription and replication in human cells, particularly focusing on R-loop structures. In our discussion, he explains the formation of R-loops and their impact on genome stability, emphasizing the importance of the orientation of replication forks approaching R-loops in determining DNA damage outcomes. Stephan then delves into his work on the MATAC-Seq method, which analyzes chromatin domains at DNA replication origins to understand replication timing variability. The method involves methylating DNA linkers between nucleosomes and using nanopore sequencing for single-molecule readouts, revealing heterogeneity in chromatin structure at replication origins. Finally, Stephan discusses his automated image analysis pipeline for quantifying transcription and replication activity overlap in mammalian genomes, addressing the challenge of visualizing these processes simultaneously. The conversation concludes with insights into Stefan's future research directions, focusing on understanding transcription-replication conflicts' molecular basis and their potential implications in cancer cell transformation. References Hamperl, S., Brown, C. R., Garea, A. V., Perez-Fernandez, J., Bruckmann, A., Huber, K., Wittner, M., Babl, V., Stoeckl, U., Deutzmann, R., Boeger, H., Tschochner, H., Milkereit, P., & Griesenbeck, J. (2014). Compositional and structural analysis of selected chromosomal domains from Saccharomyces cerevisiae. Nucleic acids research, 42(1), e2. https://doi.org/10.1093/nar/gkt891 Hamperl, S., Bocek, M. J., Saldivar, J. C., Swigut, T., & Cimprich, K. A. (2017). Transcription-Replication Conflict Orientation Modulates R-Loop Levels and Activates Distinct DNA Damage Responses. Cell, 170(4), 774–786.e19. https://doi.org/10.1016/j.cell.2017.07.043 Chanou, A., Weiβ, M., Holler, K., Sajid, A., Straub, T., Krietsch, J., Sanchi, A., Ummethum, H., Lee, C. S. K., Kruse, E., Trauner, M., Werner, M., Lalonde, M., Lopes, M., Scialdone, A., & Hamperl, S. (2023). Single molecule MATAC-seq reveals key determinants of DNA replication origin efficiency. Nucleic acids research, 51(22), 12303–12324. https://doi.org/10.1093/nar/gkad1022 Contact Epigenetics Podcast on X Epigenetics Podcast on Instagram Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Epigenetics Podcast on Threads Active Motif on X Active Motif on LinkedIn Email: podcast@activemotif.com
In this episode of the Epigenetics Podcast, we talked with Nadav Ahituv from University of California, San Francisco about his work on mutations of gene regulatory elements in human disease. Using massively parallel experiments, his lab revolutionized functional genomics by studying the impact of transcription factor binding sites on gene expression. His groundbreaking technology deciphered the regulatory language of gene expression by exploring transcription factor combinations, spacing, and orientation. By delving into the influence of DNA shape and gene topology, Nadav Ahituv's research provides a comprehensive understanding of gene regulation at the molecular level, shedding light on the complexity of genetic interactions. The conversation delves into specific cases involving enhancers, gene sequencing, and 3D genomic structure, highlighting the impact of critical elements such as CTCF sites on gene expression. Discussions of haploid insufficiency and its implications for human health, using CRISPR technology to enhance gene expression, offer new possibilities for treating genetic diseases. Explorations of leptin-responsive regulatory elements in the hypothalamus and liver-associated transcription factors provide insights into metabolic regulation and gene expression networks in different tissues. The episode also explores the epigenomic landscape, the evolution of methods from bulk approaches to single-cell analyses, and the role of AI and machine learning in deciphering complex genetic patterns. The conversation transitions to a unique study of bat embryonic development, dietary differences, and their implications for understanding wing development and metabolism in different bat species. References Ahituv, N., Zhu, Y., Visel, A., Holt, A., Afzal, V., Pennacchio, L. A., & Rubin, E. M. (2007). Deletion of ultraconserved elements yields viable mice. PLoS biology, 5(9), e234. https://doi.org/10.1371/journal.pbio.0050234 Matharu, N., Rattanasopha, S., Tamura, S., Maliskova, L., Wang, Y., Bernard, A., Hardin, A., Eckalbar, W. L., Vaisse, C., & Ahituv, N. (2019). CRISPR-mediated activation of a promoter or enhancer rescues obesity caused by haploinsufficiency. Science (New York, N.Y.), 363(6424), eaau0629. https://doi.org/10.1126/science.aau0629 Ushiki, A., Zhang, Y., Xiong, C., Zhao, J., Georgakopoulos-Soares, I., Kane, L., Jamieson, K., Bamshad, M. J., Nickerson, D. A., University of Washington Center for Mendelian Genomics, Shen, Y., Lettice, L. A., Silveira-Lucas, E. L., Petit, F., & Ahituv, N. (2021). Deletion of CTCF sites in the SHH locus alters enhancer-promoter interactions and leads to acheiropodia. Nature communications, 12(1), 2282. https://doi.org/10.1038/s41467-021-22470-z Georgakopoulos-Soares, I., Deng, C., Agarwal, V., Chan, C. S. Y., Zhao, J., Inoue, F., & Ahituv, N. (2023). Transcription factor binding site orientation and order are major drivers of gene regulatory activity. Nature communications, 14(1), 2333. https://doi.org/10.1038/s41467-023-37960-5 Gordon, W. E., Baek, S., Nguyen, H. P., Kuo, Y. M., Bradley, R., Fong, S. L., Kim, N., Galazyuk, A., Lee, I., Ingala, M. R., Simmons, N. B., Schountz, T., Cooper, L. N., Georgakopoulos-Soares, I., Hemberg, M., & Ahituv, N. (2024). Integrative single-cell characterization of a frugivorous and an insectivorous bat kidney and pancreas. Nature communications, 15(1), 12. https://doi.org/10.1038/s41467-023-44186-y Related Episodes Ultraconserved Enhancers and Enhancer Redundancy (Diane Dickel) Enhancers and Chromatin Remodeling in Mammary Gland Development (Camila dos Santos) Enhancer-Promoter Interactions During Development (Yad Ghavi-Helm) Contact Epigenetics Podcast on X Epigenetics Podcast on Instagram Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Epigenetics Podcast on Threads Active Motif on X Active Motif on LinkedIn Email: podcast@activemotif.com
In this episode of the Epigenetics Podcast, we talked with Ana Cvejic from the Biotech Research & Innovation Centre at the University of Copenhagen about her work on using sc-multiomics to characterise human developmental hematopoiesis. The conversation starts by delving into Ana's research on hematopoiesis, starting with her work on identifying novel genes controlling blood traits in zebrafish models. She explains her transition to single-cell methodologies and the application of single-cell RNA sequencing to study hematopoietic cells in zebrafish, focusing on thrombocyte lineage commitment and gene expression. The discussion progresses to her groundbreaking study on human fetal hematopoiesis, where she combined single-cell RNA-seq with single-cell ATAC-seq to understand chromatin accessibility and gene expression dynamics. Ana then shares insights into the identification of new cell surface markers and the priming of hematopoietic stem cells, particularly in conditions like Down syndrome. Furthermore, she then elaborates on the construction of a phylogenetic tree of blood development using whole-genome sequencing of single-cell-derived hematopoietic colonies from healthy human fetuses. She explains the motivation behind this study, highlighting the insights gained regarding stem cell quantities, developmental timelines, and mutations in blood development. References Bielczyk-Maczyńska, E., Serbanovic-Canic, J., Ferreira, L., Soranzo, N., Stemple, D. L., Ouwehand, W. H., & Cvejic, A. (2014). A loss of function screen of identified genome-wide association study Loci reveals new genes controlling hematopoiesis. PLoS genetics, 10(7), e1004450. https://doi.org/10.1371/journal.pgen.1004450 Athanasiadis, E. I., Botthof, J. G., Andres, H., Ferreira, L., Lio, P., & Cvejic, A. (2017). Single-cell RNA-sequencing uncovers transcriptional states and fate decisions in haematopoiesis. Nature communications, 8(1), 2045. https://doi.org/10.1038/s41467-017-02305-6 Ranzoni, A. M., Tangherloni, A., Berest, I., Riva, S. G., Myers, B., Strzelecka, P. M., Xu, J., Panada, E., Mohorianu, I., Zaugg, J. B., & Cvejic, A. (2021). Integrative Single-Cell RNA-Seq and ATAC-Seq Analysis of Human Developmental Hematopoiesis. Cell stem cell, 28(3), 472–487.e7. https://doi.org/10.1016/j.stem.2020.11.015 Related Episodes Single Cell Epigenomics in Neuronal Development (Tim Petros) ATAC-Seq, scATAC-Seq and Chromatin Dynamics in Single-Cells (Jason Buenrostro) Single-Cell Technologies using Microfluidics (Ben Hindson) Contact Epigenetics Podcast on X Epigenetics Podcast on Instagram Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Epigenetics Podcast on Threads Active Motif on X Active Motif on LinkedIn Email: podcast@activemotif.com
In this episode of the Epigenetics Podcast, we talked with Sven Heinz from the University of California in San Diego about his work on the impact of sequence variation on transcription factor binding affinities and genetic diversity. Sven Heinz talks about a landmark study published in Nature that examined the impact of sequence variation on transcription factor binding affinities and downstream effects on gene expression. Modifying genetic sequences to understand the influence of different motifs provided valuable insights into how genetic variation shapes cellular responses and gene expression patterns, underscoring the importance of genetic diversity. Methodological approaches using inducible systems to observe changes in transcription factor binding patterns highlight the critical role of motif variation and redundancy in transcription factor families. These studies provide essential insights into the complex network of transcriptional regulation and chromatin dynamics, revealing the nuanced mechanisms that control gene expression and chromatin organization. In addition, he is investigating how small nucleotide changes can significantly affect transcription factor binding in macrophages from different mouse strains, shedding light on the intricate effects of genetic variation on transcription factor binding. Sven's career path from project scientist to assistant professor at UC San Diego and the Salk Institute reflects a journey marked by serendipitous opportunities and a collaborative, innovative research environment. The podcast delves into the effects of influenza virus infection on chromosomal territories, gene transcription, and chromatin structure, unraveling the sophisticated interplay between viral infection and host cell transcriptional regulation. References Heinz, S., Benner, C., Spann, N., Bertolino, E., Lin, Y. C., Laslo, P., Cheng, J. X., Murre, C., Singh, H., & Glass, C. K. (2010). Simple combinations of lineage-determining transcription factors prime cis-regulatory elements required for macrophage and B cell identities. Molecular cell, 38(4), 576–589. https://doi.org/10.1016/j.molcel.2010.05.004 Heinz, S., Romanoski, C. E., Benner, C., Allison, K. A., Kaikkonen, M. U., Orozco, L. D., & Glass, C. K. (2013). Effect of natural genetic variation on enhancer selection and function. Nature, 503(7477), 487–492. https://doi.org/10.1038/nature12615 Texari, L., Spann, N. J., Troutman, T. D., Sakai, M., Seidman, J. S., & Heinz, S. (2021). An optimized protocol for rapid, sensitive and robust on-bead ChIP-seq from primary cells. STAR protocols, 2(1), 100358. https://doi.org/10.1016/j.xpro.2021.100358 Related Episodes Pioneer Transcription Factors and Their Influence on Chromatin Structure (Ken Zaret) Multiple Challenges in ChIP (Adam Blattler) The Role of Pioneer Factors Zelda and Grainyhead at the Maternal-to-Zygotic Transition (Melissa Harrison) Contact Epigenetics Podcast on X Epigenetics Podcast on Instagram Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Epigenetics Podcast on Threads Active Motif on X Active Motif on LinkedIn Email: podcast@activemotif.com
In this episode of the Epigenetics Podcast, we talked with Sarah Marzi from the UK Dementia Research Institute at Imperial College London about her work on epigenetic changes in Alzheimer's Disease, and comparing CUT&Tag to ENCODE ChIP-Seq using limited cell samples. The interview discusses Sarah Marzi's work on ChIP-Seq experiments and their significance in understanding Alzheimer's disease from an epigenetic perspective. The discussion touches on the widespread dysregulation and changes in acetylation, particularly in genes associated with Alzheimer's risk, providing insights into potential links between epigenetic insults and disease onset. Moving on to the technical aspects of the study, the interview examines the strategic use of CUT&Tag. It explores the challenges and optimizations involved in accurately profiling limited cell samples. The dialogue also compares CUT&Tag to ENCODE ChIP-Seq, highlighting the complexities of peak calling and data interpretation across different methodologies. References Kumsta, R., Marzi, S., Viana, J. et al. Severe psychosocial deprivation in early childhood is associated with increased DNA methylation across a region spanning the transcription start site of CYP2E1. Transl Psychiatry 6, e830 (2016). https://doi.org/10.1038/tp.2016.95 Marzi, S. J., Schilder, B. M., Nott, A., Frigerio, C. S., Willaime‐Morawek, S., Bucholc, M., Hanger, D. P., James, C., Lewis, P. A., Lourida, I., Noble, W., Rodriguez‐Algarra, F., Sharif, J., Tsalenchuk, M., Winchester, L. M., Yaman, Ü., Yao, Z., The Deep Dementia Phenotyping (DEMON) Network, Ranson, J. M., & Llewellyn, D. J. (2023). Artificial intelligence for neurodegenerative experimental models. Alzheimer’s & Dementia, 19(12), 5970–5987. https://doi.org/10.1002/alz.13479 Marzi, S. J., Leung, S. K., Ribarska, T., Hannon, E., Smith, A. R., Pishva, E., Poschmann, J., Moore, K., Troakes, C., Al-Sarraj, S., Beck, S., Newman, S., Lunnon, K., Schalkwyk, L. C., & Mill, J. (2018). A histone acetylome-wide association study of Alzheimer’s disease identifies disease-associated H3K27ac differences in the entorhinal cortex. Nature Neuroscience, 21(11), 1618–1627. https://doi.org/10.1038/s41593-018-0253-7 Hu, D., Abbasova, L., Schilder, B. M., Nott, A., Skene, N. G., & Marzi, S. J. (2022). CUT&Tag recovers up to half of ENCODE ChIP-seq peaks in modifications of H3K27 [Preprint]. Genomics. https://doi.org/10.1101/2022.03.30.486382 Related Episodes When is a Peak a Peak? (Claudio Cantù) Development of Integrative Machine Learning Tools for Neurodegenerative Diseases (Enrico Glaab) DNA Methylation Alterations in Neurodegenerative Diseases (Paula Desplats) Contact Epigenetics Podcast on X Epigenetics Podcast on Instagram Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Epigenetics Podcast on Threads Active Motif on X Active Motif on LinkedIn Email: podcast@activemotif.com
In this episode of the Epigenetics Podcast, we talked with Mark Parthun from Ohio State University about his work on the role of Hat1p in chromatin assembly. Mark Parthun shares insights into his pivotal paper in 2004 that explored the link between type B histone acetyltransferases and chromatin assembly, setting the stage for his current research interests in epigenetics. He highlights the role of HAT1 in acetylating lysines on newly synthesized histones, its involvement in double-strand break repair, and the search for phenotypes associated with HAT1 mutations. The discussion expands to a collaborative research project between two scientists uncovering the roles of HAT1 and NASP as chaperones in chromatin assembly. Transitioning from yeast to mouse models, the team investigated the effects of HAT1 knockout on mouse phenotypes, particularly in lung development and craniofacial morphogenesis. They also explored the impact of histone acetylation on chromatin dynamics and its influence on lifespan, aging processes, and longevity. References Parthun, M. R., Widom, J., & Gottschling, D. E. (1996). The Major Cytoplasmic Histone Acetyltransferase in Yeast: Links to Chromatin Replication and Histone Metabolism. Cell, 87(1), 85–94. https://doi.org/10.1016/S0092-8674(00)81325-2 Kelly, T. J., Qin, S., Gottschling, D. E., & Parthun, M. R. (2000). Type B histone acetyltransferase Hat1p participates in telomeric silencing. Molecular and cellular biology, 20(19), 7051–7058. https://doi.org/10.1128/MCB.20.19.7051-7058.2000 Ai, X., & Parthun, M. R. (2004). The nuclear Hat1p/Hat2p complex: a molecular link between type B histone acetyltransferases and chromatin assembly. Molecular cell, 14(2), 195–205. https://doi.org/10.1016/s1097-2765(04)00184-4 Nagarajan, P., Ge, Z., Sirbu, B., Doughty, C., Agudelo Garcia, P. A., Schlederer, M., Annunziato, A. T., Cortez, D., Kenner, L., & Parthun, M. R. (2013). Histone acetyl transferase 1 is essential for mammalian development, genome stability, and the processing of newly synthesized histones H3 and H4. PLoS genetics, 9(6), e1003518. https://doi.org/10.1371/journal.pgen.1003518 Agudelo Garcia, P. A., Hoover, M. E., Zhang, P., Nagarajan, P., Freitas, M. A., & Parthun, M. R. (2017). Identification of multiple roles for histone acetyltransferase 1 in replication-coupled chromatin assembly. Nucleic Acids Research, 45(16), 9319–9335. https://doi.org/10.1093/nar/gkx545 Popova, L. V., Nagarajan, P., Lovejoy, C. M., Sunkel, B. D., Gardner, M. L., Wang, M., Freitas, M. A., Stanton, B. Z., & Parthun, M. R. (2021). Epigenetic regulation of nuclear lamina-associated heterochromatin by HAT1 and the acetylation of newly synthesized histones. Nucleic Acids Research, 49(21), 12136–12151. https://doi.org/10.1093/nar/gkab1044 Related Episodes Regulation of Chromatin Organization by Histone Chaperones (Geneviève Almouzni) Effects of Non-Enzymatic Covalent Histone Modifications on Chromatin (Yael David) scDamID, EpiDamID and Lamina Associated Domains (Jop Kind) Contact Epigenetics Podcast on X Epigenetics Podcast on Instagram Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Epigenetics Podcast on Threads Active Motif on X Active Motif on LinkedIn Email: podcast@activemotif.com
In this episode of the Epigenetics Podcast, we talked with Upasna Sharma from UC Santa Cruz about her work on a number of interesting projects on H2A.Z and telomeres, the impact of paternal diet on offspring metabolism, and the role of small RNAs in sperm. In this interview Upasna Sharma discusses her work on the study of the paternal diet's impact on offspring metabolism. She reveals the discovery of small non-coding RNAs, particularly tRNA fragments, in mature mammalian sperm that may carry epigenetic information to the next generation. She explains the specific alterations in tRNA fragment levels in response to a low-protein diet and the connections found between tRNA fragments and metabolic status. Dr. Sharma further explains the degradation and stabilization of tRNA fragments in cells and the processes involved in their regulation. She shares their observation of tRNA fragment abundance in epididymal sperm, despite the sperm being transcriptionally silent at that time. This leads to a discussion on the role of the epididymis in the reprogramming of small RNA profiles and the transportation of tRNA fragments through extracellular vesicles. The conversation then shifts towards the potential mechanism of how environmental information could be transmitted to sperm and the observed changes in small RNAs in response to a low-protein diet. Dr. Sharma discusses the manipulation of small RNAs in embryos and mouse embryonic stem cells, revealing their role in regulating specific sets of genes during early development. However, the exact mechanisms that link these early changes to metabolic phenotypes are still being explored. References Sharma, U., Conine, C. C., Shea, J. M., Boskovic, A., Derr, A. G., Bing, X. Y., Belleannee, C., Kucukural, A., Serra, R. W., Sun, F., Song, L., Carone, B. R., Ricci, E. P., Li, X. Z., Fauquier, L., Moore, M. J., Sullivan, R., Mello, C. C., Garber, M., & Rando, O. J. (2016). Biogenesis and function of tRNA fragments during sperm maturation and fertilization in mammals. Science (New York, N.Y.), 351(6271), 391–396. https://doi.org/10.1126/science.aad6780 Sharma, U., Sun, F., Conine, C. C., Reichholf, B., Kukreja, S., Herzog, V. A., Ameres, S. L., & Rando, O. J. (2018). Small RNAs Are Trafficked from the Epididymis to Developing Mammalian Sperm. Developmental cell, 46(4), 481–494.e6. https://doi.org/10.1016/j.devcel.2018.06.023 Rinaldi, V. D., Donnard, E., Gellatly, K., Rasmussen, M., Kucukural, A., Yukselen, O., Garber, M., Sharma, U., & Rando, O. J. (2020). An atlas of cell types in the mouse epididymis and vas deferens. eLife, 9, e55474. https://doi.org/10.7554/eLife.55474 Related Episodes The Epigenetics of Human Sperm Cells (Sarah Kimmins) Transgenerational Inheritance and Evolution of Epimutations (Peter Sarkies) The Role of Small RNAs in Transgenerational Inheritance in C. elegans (Oded Rechavi) Contact Epigenetics Podcast on X Epigenetics Podcast on Instagram Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Epigenetics Podcast on Threads Active Motif on X Active Motif on LinkedIn Email: podcast@activemotif.com
In this episode of the Epigenetics Podcast, we talked with Weiwei Dang from Baylor College of Medicine about his work on molecular mechanisms of aging and the role of H3K36me3 and cryptic transcription in cellular aging. The team in the Weiwei Dang lab explored the connection between histone marks, specifically H4K16 acetylation and H3K36 methylation, and aging. Dr. Dang describes how the lab conducted experiments by mutating H4K16 to determine its effect on lifespan. They observed that the mutation to glutamine accelerated the aging process and shortened lifespan, providing causal evidence for the relationship between H4K16 and lifespan. They also discovered that mutations in acetyltransferase and demethylase enzymes had opposite effects on lifespan, further supporting a causal relationship. Weiwei Dang then discusses their expanded research on aging, conducting high-throughput screens to identify other histone residues and mutants in yeast that regulate aging. They found that most mutations at K36 shortened lifespan, and so they decided to follow up on a site that is known to be methylated and play a role in gene function. They discovered that H3K36 methylation helps suppress cryptic transcription, which is transcription that initiates from within the gene rather than at the promoter. Mutants lacking K36 methylation showed an aging phenotype. They also found evidence of cryptic transcription in various datasets related to aging and senescence, including C. elegans and mammalian cells. References Dang, W., Steffen, K., Perry, R. et al. Histone H4 lysine 16 acetylation regulates cellular lifespan. Nature 459, 802–807 (2009). https://doi.org/10.1038/nature08085 Sen, P., Dang, W., Donahue, G., Dai, J., Dorsey, J., Cao, X., Liu, W., Cao, K., Perry, R., Lee, J. Y., Wasko, B. M., Carr, D. T., He, C., Robison, B., Wagner, J., Gregory, B. D., Kaeberlein, M., Kennedy, B. K., Boeke, J. D., & Berger, S. L. (2015). H3K36 methylation promotes longevity by enhancing transcriptional fidelity. Genes & development, 29(13), 1362–1376. https://doi.org/10.1101/gad.263707.115 Yu, R., Cao, X., Sun, L. et al. Inactivating histone deacetylase HDA promotes longevity by mobilizing trehalose metabolism. Nat Commun 12, 1981 (2021). https://doi.org/10.1038/s41467-021-22257-2 McCauley, B.S., Sun, L., Yu, R. et al. Altered chromatin states drive cryptic transcription in aging mammalian stem cells. Nat Aging 1, 684–697 (2021). https://doi.org/10.1038/s43587-021-00091-x Related Episodes Epigenetic Mechanisms of Aging and Longevity (Shelley Berger) Epigenetic Clocks and Biomarkers of Ageing (Morgan Levine) Gene Dosage Alterations in Evolution and Ageing (Claudia Keller Valsecchi) Contact Epigenetics Podcast on X Epigenetics Podcast on Instagram Epigenetics Podcast on Mastodon Epigenetics Podcast on Bluesky Epigenetics Podcast on Threads Active Motif on X Active Motif on LinkedIn Email: podcast@activemotif.com