Seminario INGEBI

Martes 20 de Noviembre 13:20 hs.

Dr. Razvan Chereji

Research Fellow, NIH

Precise genome-wide mapping of single nucleosomes and linkers in vivo

We developed a chemical cleavage method that allows us to map both single nucleosomes and linkers with high accuracy genome-wide in yeast. Our single nucleosome positioning data reveal that nucleosomes occupy preferred positions that differ by integral multiples of the DNA helical repeat. By comparing nucleosome dyad positioning maps to existing genomic and transcriptomic data, we evaluated the contributions of sequence, transcription, histone H1 and H2A.Z in defining the chromatin landscape. We present a biophysical model that neglects DNA sequence and shows that steric occlusion suffices to explain the salient features of nucleosome positioning in yeast and in higher organisms. (Joint work with Srinivas Ramachandran, Terri D. Bryson and Steven Henikoff)