Two distinct nucleosome alterations characterize chromatin remodeling at the Saccharomyces cerevisiae ADH2 promoter

Glucose depletion derepresses the Saccharomyces cerevisiae ADH2 gene; this metabolic change is accompanied by chromatin structural modifications in the promoter region. We show that the ADR6/SWI1 gene is not necessary for derepression of the wild type chromosomal ADH2, whereas the transcription factor Adr1p, which regulates several S. cerevisiae functions, plays a major role in driving nucleosome reconfiguration and ADH2 expression. When we tested the effect of individual domains of the regulatory protein Adr1p on the chromatin structure of ADH2, a remodeling consisting of at least two steps was observed. Adr1p derivatives were analyzed in derepressing conditions, showing that the Adr1p DNA binding domain alone causes an alteration in chromatin organization in the absence of transcription. This alteration differs from the remodeling observed in the presence of the Adr1p activation domain when the promoter is transcriptionally active.