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 th e promoter region. We show that the ADR6/SWI1 gene is not necessary for der epression of the wild type chromosomal ADH2, whereas the transcription fact or Adr1p, which regulates several S. cerevisiae functions, plays a major ro le in driving nucleosome reconfiguration and ADH2 expression. When we teste d the effect of individual domains of the regulatory protein Adr1p on the c hromatin structure of ADH2, a remodeling consisting of at least two steps w as observed, Adr1p derivatives were analyzed in derepressing conditions, sh owing that the Adr1p DNA binding domain alone causes an alteration in chrom atin 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.