In this episode of the Epigenetics Podcast, we talked with Viviana Risca from Rockefeller University about her work on RICC-Seq and how it's used to probe DNA-DNA contacts in intact or fixed cells using ionizing radiation.

This Interview covers Dr. Viviana Risca's cutting-edge methodologies, such as RICC-seq, which enables high-resolution analysis of chromatin structures without traditional cross-linking biases. We engage in a detailed discussion about how different techniques, such as RICC-seq and Micro-C, complement each other to provide robust insights into nucleosome interactions and chromatin dynamics. Dr. Risca articulates the challenges and innovations within her lab as it navigates through the complexities of chromatin mapping.

The episode takes an exciting turn toward traversing the landscape of her future research directions, particularly studying the role of linker histones and other chromatin architectural proteins in regulating gene expression. Dr. Risca emphasizes the importance of understanding chromatin's mechanical properties and how these influence cellular processes like transcriptional regulation, DNA replication, and cellular responses to damage.

We also explore her collaborative work that bridges the gap between basic research and clinical applications, particularly in cancer therapy. Dr. Risca shares insights into her investigations into how chromatin dynamics change during cell cycle arrest and their implications for cancer therapy resistance. Our discussion culminates in her reflections on the definition of epigenetics, framing it as the exploration of how cellular mechanisms encode and process information.

Risca VI, Denny SK, Straight AF, Greenleaf WJ. Variable chromatin structure revealed by in situ spatially correlated DNA cleavage mapping. Nature. 2017 Jan 12;541(7636):237-241. doi: 10.1038/nature20781. Epub 2016 Dec 26. PMID: 28024297; PMCID: PMC5526328.

Soroczynski J, Anderson LJ, Yeung JL, Rendleman JM, Oren DA, Konishi HA, Risca VI. OpenTn5: Open-Source Resource for Robust and Scalable Tn5 Transposase Purification and Characterization. bioRxiv [Preprint]. 2024 Jul 13:2024.07.11.602973. doi: 10.1101/2024.07.11.602973. PMID: 39026714; PMCID: PMC11257509.

Prescott, N. A., Biaco, T., Mansisidor, A., Bram, Y., Rendleman, J., Faulkner, S. C., Lemmon, A. A., Lim, C., Tiersky, R., Salataj, E., Garcia-Martinez, L., Borges, R. L., Morey, L., Hamard, P.-J., Koche, R. P., Risca, V. I., Schwartz, R. E., & David, Y. (2025). A nucleosome switch primes hepatitis B virus infection. Cell, S0092867425001023. https://doi.org/10.1016/j.cell.2025.01.033

Hi-C and Three-Dimensional Genome Sequencing (Erez Lieberman Aiden)

Split-Pool Recognition of Interactions by Tag Extension (SPRITE) (Mitch Guttman)

Effects of Non-Enzymatic Covalent Histone Modifications on Chromatin (Yael David)

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