Biophysical Society Thematic Meeting| Les Houches 2019

Multiscale Modeling of Chromatin: Bridging Experiment with Theory

Poster Abstracts

6-POS Board 6 THE PACKING OF MAMMALIAN CHROMOSOME: A PHASE TRANSITION PERSPECTIVE Yiqin Gao 1 ; 1 Peking University, College of Chemistry and Molecular Engineering, Beijing, Beijing, China The chromatin structure plays important roles in gene regulation. Several models have been proposed about the relationship between epigenetics as well as transcription factors and chromatin structure. However, our understanding of chromatin structure formation in different cell types and how chromatin 3D structures including TAD and compartment are determined or affected by the most fundamental feature, DNA sequences, are far from clear. We identified two types of genomic domains (called forests and prairies) based on the uneven sequential distribution of CGIs and found them to be genetically, epigenetically, transcriptionally, and structurally distinct. The specific interactions of the two domain types relate to cell-type specific gene regulation and cell-identity establishment. Meanwhile, they continue to spatially segregate from each other in development, differentiation and senescence at multiple scales. Furthermore, spatial separation of the two domains prompts us to propose a phase separation mechanism for chromatin structure formation. This mechanism allows us to discuss in a unified framework the chromatin structure formation in various biological events, including development, differentiation and senescence. In this talk, we will also discuss possible biological consequences emerging naturally from domain segregation and the phase separation mechanism including the temperature dependence of chromatin structures, and speculated that the variation in sequential mosaicity between species may relate to their important biological differences.

49