Book of Abstracts: Albany 2011
June 14-18 2011
©Adenine Press (2010)
A Genomic Code for Nucleosome Positioning from Archaebacteria to Man
Eukaryotic genomes are packaged into nucleosome particles that occlude the DNA from interacting with most DNA binding proteins. We have discovered that genomes care where their nucleosomes are located on average, and that genomes manifest this care by encoding an additional layer of genetic information, superimposed on top of other kinds of regulatory and coding information that were previously recognized. The physical basis of the nucleosome DNA sequences preferences lies in the sequence-dependent mechanics of DNA itself. We have an increasingly good ability to read this nucleosome positioning information and predict the in vivo locations of nucleosomes. Our results suggest that genomes utilize this nucleosome positioning code to facilitate specific chromosome functions, including to define the next higher level of chromosome structure itself. Comparisons across diverse organisms suggests that basic aspects of this nucleosome positioning code are conserved from archaebacteria to man. While we now have a good theoretical and experimental understanding of the approximate locations of nucleosomes in vivo, many aspects of chromosome structure and function hinge on knowing nucleosome locations to basepair resolution; and current experimental mapping methods do not come close to achieving such accuracy. I will discuss a new experimental approach to obtaining nucleosome maps with true basepair resolution, and novel discoveries resulting from the use of this methodology.
Department of Molecular Biosciences and Department of Chemistry