Sep 30, 2014
from 11:00 AM to 12:00 PM
|Contact Name||Amanda Chang|
Open to the public
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"H1 Linker Histones: Versatile Regulators of Chromatin Structure and Genetic Activity"
Arthur Skoultchi, PhD
Chair and Professor Department of Cell Biology
Albert Einstein College
Bio: Dr. Skoultchi received his AB in Physics from Princeton University in 1962 and his PhD in Molecular Biophysics and Biochemistry from Yale University in 1960. His current research interests are in normal and malignant blood cell development, control of the cell cycle and its relationship to differentiation, transcriptional regulation of gene expression, and chromatin structure and function. We are currently studying the role of two master regulators of blood cell development, PU.1 and GATA-1, and factors that associate with them and how these factors regulate proliferation and differentiation in red blood cells. He is the recipient of the National Cancer Institute Merit Grant Award (1990-1998), the Irma T. Hirschl Career Scientist Award (1979-1984), and theAmerican Cancer Society Faculty Research Award (1974-1979).
Abstract: Eukaryotic genomes are packaged into chromatin, which is composed of highly conserved repetitive units called nucleosomes. Nucleosome core particles consist of about 145 base pairs of DNA organized around octamers of the four core histones, H2A, H2B, H3 and H4. Chromatin also contains a fifth histone, the linker histone H1. Whereas, there are several types of core histone variants, the H1 linker histone family is by far the most diverse. For example, mice express 11 non-allelic H1 variants or subtypes that differ in their primary sequences and in their expression during development. We are studying the functions of H1 in mice, and also in the fruit fly Drosophila melanogaster, which expresses a single H1 during most of its development.
Regulation of genetic activity during development is a complex process involving the activation and silencing of genes at multiple levels. H1 participates in these processes through its ability to regulate chromatin structure. Recently however, we found that H1 plays an unexpected direct role in epigenetic marking of chromatin. In both Drosophila and mice, H1 helps to regulate post-translational modifications of core histones. And in mammals, H1 also helps to regulate DNA methylation. Surprisingly, H1 carries out these functions by interacting with and helping to recruit histone and DNA modifying enzymes to chromatin. H1 can also block access of modifying enzymes to specific histone residues in nucleosome core particles. We have also found that the mouse H1 subtypes differ in their epigenetic regulatory activities, suggesting that changes in their expression during development provides additional levels of regulation of chromatin function. Our studies indicate that H1 linker histones are highly versatile regulators of chromatin structure and genetic activity.
Hosted By: Bill Marzluff