In this episode of the Epigenetics Podcast, we talked with Tomohisa Toda from the Max-Planck-Zentrum für Physik und Medizin about his work on the long-term maintenance of neuronal identity, with a focus on epigenetic and RNA-based mechanisms in brain stability and aging.

Dr. Toda describes how brain circuits are stabilized over time, why critical periods are temporally restricted, and how epigenetic regulation may help maintain established neural identity. This led him to postdoctoral work on neural stem cells and long-term maintenance.

We cover his work on nuclear pore and nuclear lamina proteins, including NUP153 and Lamin B1. He explains that NUP153 is enriched in neural stem cells and appears to act as a platform for recruiting factors that help maintain the stem cell epigenome. For Lamin B1, we discuss its decline during aging, how its loss can lead to stem cell exhaustion, reduced adult neurogenesis, and age-related mood dysregulation in the hippocampus.

We also discuss LINE-1 RNA, where we learn that reducing LINE-1 promotes neural progenitor differentiation. He explains that this effect is linked to the RNA sequence itself rather than retrotransposition, based on rescue experiments.

Finally, we talk about his finding that a subset of postnatally born brain cells contains nuclear RNAs that remain detectable for up to two years. He describes their nuclear enrichment, possible association with heterochromatin, and ongoing work to understand their sequence features, modifications, and biological function.

• Bedrosian, T. A., Houtman, J., Eguiguren, J. S., Ghassemzadeh, S., Rund, N., Novaresi, N. M., Hu, L., Parylak, S. L., Denli, A. M., Randolph-Moore, L., Namba, T., Gage, F. H., & Toda, T. (2021). Lamin B1 decline underlies age-related loss of adult hippocampal neurogenesis. The EMBO journal, 40(3), e105819. https://doi.org/10.15252/embj.2020105819
• Zocher, S., McCloskey, A., Karasinsky, A., Schulte, R., Friedrich, U., Lesche, M., Rund, N., Gage, F. H., Hetzer, M. W., & Toda, T. (2024). Lifelong persistence of nuclear RNAs in the mouse brain. Science (New York, N.Y.), 384(6691), 53–59. https://doi.org/10.1126/science.adf3481
• Zhilina, D., Bolaños Castro, L. A., Eguiguren, J. S., Zocher, S., Karasinsky, A., Widmer, D., Espinós, A., Borrell, V., Brand, M., Miura, K., Zierau, O., Yun, M. H., & Toda, T. (2026). Dynamic expression of lamin B1 during adult neurogenesis in the vertebrate brain. Developmental dynamics : an official publication of the American Association of Anatomists, 255(2), 187–208. https://doi.org/10.1002/dvdy.70023

• Characterizing Chromatin at the Nuclear Lamina (Bas van Steensel)
• Single Cell Epigenomics in Neuronal Development (Tim Petros)
• The Role of Histone Dopaminylation and Serotinylation in Neuronal Plasticity (Ian Maze)

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In this episode of the Epigenetics Podcast, we talked with Tae-Kyung Kim from POSTECH in South Korea about the discovery and characterisation of enhancer RNAs.

Dr. Kim describes joining Danny Reinberg’s lab as a graduate student, where he was trained in protein biochemistry and general transcription mechanisms. He recalls this period as a formative time, when research on transcription factors and RNA polymerase II was rapidly advancing and many findings were still novel.

Kim then moved into neurobiology through Michael Greenberg’s lab, where he first worked on a project related to L-type voltage-gated channels. He says his work shifted toward chromatin and gene regulation in neurons after learning that chromatin immunoprecipitation could be applied to neuronal systems and after the arrival of next-generation sequencing.

He explains that eRNAs were discovered in his lab through RNA-seq and ChIP-seq data from neuronal activity experiments, especially around the FOS locus. He later showed that eRNAs are transcribed from enhancers, are typically unstable, often lack splicing and polyadenylation, and have defined initiation sites, suggesting regulated transcription.

Kim says eRNAs can interact with transcription and epigenetic regulators, including factors involved in pause release and mediator complexes. He describes experiments showing that eRNA knockdown reduced ARC induction and that eRNA production depends on proper enhancer-promoter contact.

He concludes by describing newer work in his lab using spatial transcriptomics and eRNA-based reporter systems to map active neural populations, including studies related to cocaine-responsive circuits. He says his future work will focus on spatial technologies to better understand brain organization and function at molecular resolution.

• Kim TK, Hemberg M, Gray JM, Costa AM, Bear DM, Wu J, Harmin DA, Laptewicz M, Barbara-Haley K, Kuersten S, Markenscoff-Papadimitriou E, Kuhl D, Bito H, Worley PF, Kreiman G, Greenberg ME. Widespread transcription at neuronal activity-regulated enhancers. Nature. 2010 May 13;465(7295):182-7. doi: 10.1038/nature09033. Epub 2010 Apr 14. PMID: 20393465; PMCID: PMC3020079.
• Schaukowitch K, Joo JY, Liu X, Watts JK, Martinez C, Kim TK. Enhancer RNA facilitates NELF release from immediate early genes. Mol Cell. 2014 Oct 2;56(1):29-42. doi: 10.1016/j.molcel.2014.08.023. Epub 2014 Sep 25. PMID: 25263592; PMCID: PMC4186258.
• Kim SK, Liu X, Park J, Um D, Kilaru G, Chiang CM, Kang M, Huber KM, Kang K, Kim TK. Functional coordination of BET family proteins underlies altered transcription associated with memory impairment in fragile X syndrome. Sci Adv. 2021 May 19;7(21):eabf7346. doi: 10.1126/sciadv.abf7346. PMID: 34138732; PMCID: PMC8133748.
• Gorbovytska V, Kim SK, Kuybu F, Götze M, Um D, Kang K, Pittroff A, Brennecke T, Schneider LM, Leitner A, Kim TK, Kuhn CD. Enhancer RNAs stimulate Pol II pause release by harnessing multivalent interactions to NELF. Nat Commun. 2022 May 4;13(1):2429. doi: 10.1038/s41467-022-29934-w. PMID: 35508485; PMCID: PMC9068813.

• 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)

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In this episode of the Epigenetics Podcast, we talked with Peter Becker from the Biomedical Center Munich about his successful career in Epigenetics, where he discovered the chromatin remodeler ISWI and dosage compensation complex MOF.

Dr. Becker shares thoughts about his postdoctoral work with Carl Wu, where he developed embryo extract systems for studying chromatin assembly and transcription. He explains how work on Drosophila extracts led to the purification of ATP-dependent remodeling factors, including ISWI-related complexes, and how these studies showed that such factors slide nucleosomes and help organize chromatin.

We also cover his move to EMBL and later to Munich, where his lab expanded into dosage compensation in Drosophila. He describes work on the MSL complex targeting, MRE sequences, ROX RNA, DNA shape features, and how biochemical reconstitution was used to study how the complex recognizes the X chromosome.

Finally, we discuss his later work on TIP-60 and histone acetylation, including acetylome studies, and his reflections on leadership roles at EMBL and on the use of the term epigenetics. He emphasizes that epigenetics should be understood as one layer among genetics, environment, and socialization, not as a replacement for genetics.

• Tsukiyama, T., Becker, P. B., & Wu, C. (1994). ATP-dependent nucleosome disruption at a heat-shock promoter mediated by binding of GAGA transcription factor. Nature, 367(6463), 525–532. https://doi.org/10.1038/367525a0
• Varga-Weisz, P. D., Wilm, M., Bonte, E., Dumas, K., Mann, M., & Becker, P. B. (1997). Chromatin-remodelling factor CHRAC contains the ATPases ISWI and topoisomerase II. Nature, 388(6642), 598–602. https://doi.org/10.1038/41587
• Corona, D. F., Längst, G., Clapier, C. R., Bonte, E. J., Ferrari, S., Tamkun, J. W., & Becker, P. B. (1999). ISWI is an ATP-dependent nucleosome remodeling factor. Molecular cell, 3(2), 239–245. https://doi.org/10.1016/s1097-2765(00)80314-7
• Akhtar, A., & Becker, P. B. (2000). Activation of transcription through histone H4 acetylation by MOF, an acetyltransferase essential for dosage compensation in Drosophila. Molecular cell, 5(2), 367–375. https://doi.org/10.1016/s1097-2765(00)80431-1
• Akhtar, A., Zink, D., & Becker, P. B. (2000). Chromodomains are protein-RNA interaction modules. Nature, 407(6802), 405–409. https://doi.org/10.1038/35030169
• Villa, R., Schauer, T., Smialowski, P., Straub, T., & Becker, P. B. (2016). PionX sites mark the X chromosome for dosage compensation. Nature, 537(7619), 244–248. https://doi.org/10.1038/nature19338

• Dosage Compensation in Drosophila (Asifa Akhtar)
• DNase Hypersensitive Sites and Chromatin Remodeling Enzymes (Carl Wu)
• The Mechanism of ATP-dependent Remodelers and HP1 Gene Silencing (Geeta Narlikar)
• Regulation of Chromatin Organization by Histone Chaperones (Geneviève Almouzni)

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