Open AccessGlobal Chromatin Structure of 45,000 Base Pairs of Chromosome III in a- and α-Cell Yeast and during Mating-Type Switching
Author(s) -
Sevinç Ercan,
Robert T. Simpson
Publication year - 2004
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.24.22.10026-10035.2004
Subject(s) - chromatin , biology , genetics , nucleosome , mating of yeast , enhancer , mating type , hypersensitive site , chia pet , chromosome , dnase i hypersensitive site , scaffold/matrix attachment region , deoxyribonuclease i , microbiology and biotechnology , chromatin remodeling , gene , base sequence , gene expression
Directionality of yeast mating-type switching has been attributed to differences in chromatin structure for the left arm of chromosome III. We have mapped the structure of approximately 45 kbp of the left arm of chromosome III in a and alpha cells in logarithmically growing cultures and in a cells during switching. Distinctive features of chromatin structure were the occurrence of DNase I-hypersensitive sites in the promoter region of nearly every gene and some replication origins and the presence of extended regions of positioned nucleosomes in approximately 25% of the open reading frames. Other than the recombination enhancer, chromatin structures were identical in the two cell types. Changes in chromatin structure during switching were confined to the recombination enhancer. This unbiased analysis of an extended region of chromatin reveals that significant features of organized chromatin exist for the entire region, and these features are largely static with respect to mating type and mating-type switching. Our analysis also shows that primary chromatin structure does not cause the documented differences in recombinational frequency of the left arm of chromosome III in yeast a and alpha cells.