Tel-Aviv University - Computer Science Colloquium

Sunday, April 23, 2006, 11:15-12:15

Room 309
Schreiber Building


Eran Segal

Weizmann Institute

Title: A Genomic Code for Nucleosome Positioning and Chromosome Function



To fit within the nucleus, DNA of eukaryotic genomes is highly compacted

into protein-DNA complexes known as nucleosomes. Nucleosomes act as general

inhibitors, since DNA wrapped in nucleosomes is occluded from access to most

DNA binding proteins. Thus, understanding the driving forces and mechanism

by which nucleosomes are placed along the genome has important implications

for all aspects of gene regulation and chromosome function. In this study,

we combined a statistical mechanics based computational approach with

wet-lab experiments to discover and decode a new kind of genetic

information, encoded in the genomes of all eukaryotes, that specifies the

organization and positioning of nucleosomes. We show that this nucleosome

positioning code occurs abundantly across the entire genome and is highly

conserved from yeast to human. We show that this novel positioning code can,

on its own, successfully predict ~50% of the entire in vivo nucleosome

organization. We also prove the correctness of this code in in vitro

experiments. Our results establish that genomes utilize this nucleosome

positioning code to direct transcription factors to their appropriate

binding sites in the genome, and to facilitate many other specific

chromosome functions, including transcription initiation, and even

remodeling of the nucleosomes themselves.


The talk will assume no prior knowledge of Molecular Biology.