Open AccessActivation of Saccharomyces cerevisiae HIS3 Results in Gcn4p-Dependent, SWI/SNF-Dependent Mobilization of Nucleosomes over the Entire Gene
Author(s) -
Yeonjung Kim,
Neil McLaughlin,
Kim Lindstrom,
Toshio Tsukiyama,
David Clark
Publication year - 2006
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.00678-06
Subject(s) - swi/snf , nucleosome , chromatin , chromatin structure remodeling (rsc) complex , saccharomyces cerevisiae , chromatin remodeling , biology , microbiology and biotechnology , genetics , gene
Theeffects of transcriptional activation on the chromatin structure of theSaccharomyces cerevisiae HIS3 gene wereaddressed by mapping the precise positions of nucleosomes in uninducedand induced chromatin. In the absence of the Gcn4p activator,theHIS3 gene is organized into a predominant nucleosomalarray. In wild-type chromatin, this array is disrupted, and severalalternative overlapping nucleosomal arrays are formed. The disruptionof the predominant array also requires the SWI/SNF remodeling machine,indicating that the SWI/SNF complex plays an important role innucleosome mobilization over the entireHIS3 gene. The Isw1remodeling complex plays a more subtle role in determining nucleosomepositions onHIS3 , favoring positions different from thosepreferred by the SWI/SNF complex. Both the SWI/SNF and Isw1 complexesare constitutively present inHIS3 chromatin, although Isw1tends to be excluded from theHIS3 promoter. Despite theapparent disorder ofHIS3 chromatin generated by the formationof multiple nucleosomal arrays, nucleosome density profiles indicatethat some long-range order is always present. We propose that Gcn4pstimulates nucleosome mobilization over the entireHIS3 geneby the SWI/SNF complex. We suggest that the net effect of interplayamong remodeling machines atHIS3 is to create a highlydynamic chromatinstructure.