TY - JOUR

T1 - Nucleosome structure of the yeast CHA1 promoter

T2 - analysis of activation-dependent chromatin remodeling of an RNA-polymerase-II-transcribed gene in TBP and RNA pol II mutants defective in vivo in response to acidic activators

AU - Moreira, José Manuel Alfonso

AU - Holmberg, S

PY - 1998

Y1 - 1998

N2 - The Saccharomyces cerevisiae CHA1 gene encodes the catabolic L-serine (L-threonine) dehydratase. We have previously shown that the transcriptional activator protein Cha4p mediates serine/threonine induction of CHA1 expression. We used accessibility to micrococcal nuclease and DNase I to determine the in vivo chromatin structure of the CHA1 chromosomal locus, both in the non-induced state and upon induction. Upon activation, a precisely positioned nucleosome (nuc-1) occluding the TATA box and the transcription start site is removed. A strain devoid of Cha4p showed no chromatin alteration under inducing conditions. Five yeast TBP mutants defective in different steps in activated transcription abolished CHA1 expression, but failed to affect induction-dependent chromatin rearrangement of the promoter region. Progressive truncations of the RNA polymerase II C-terminal domain caused a progressive reduction in CHA1 transcription, but no difference in chromatin remodeling. Analysis of swi1, swi3, snf5 and snf6, as well as gcn5, ada2 and ada3 mutants, suggested that neither the SWI/SNF complex nor the ADA/GCN5 complex is involved in efficient activation and/or remodeling of the CHA1 promoter. Interestingly, in a sir4 deletion strain, repression of CHA1 is partly lost and activator-independent remodeling of nuc-1 is observed. We propose a model for CHA1 activation based on promoter remodeling through interactions of Cha4p with chromatin components other than basal factors and associated proteins.

AB - The Saccharomyces cerevisiae CHA1 gene encodes the catabolic L-serine (L-threonine) dehydratase. We have previously shown that the transcriptional activator protein Cha4p mediates serine/threonine induction of CHA1 expression. We used accessibility to micrococcal nuclease and DNase I to determine the in vivo chromatin structure of the CHA1 chromosomal locus, both in the non-induced state and upon induction. Upon activation, a precisely positioned nucleosome (nuc-1) occluding the TATA box and the transcription start site is removed. A strain devoid of Cha4p showed no chromatin alteration under inducing conditions. Five yeast TBP mutants defective in different steps in activated transcription abolished CHA1 expression, but failed to affect induction-dependent chromatin rearrangement of the promoter region. Progressive truncations of the RNA polymerase II C-terminal domain caused a progressive reduction in CHA1 transcription, but no difference in chromatin remodeling. Analysis of swi1, swi3, snf5 and snf6, as well as gcn5, ada2 and ada3 mutants, suggested that neither the SWI/SNF complex nor the ADA/GCN5 complex is involved in efficient activation and/or remodeling of the CHA1 promoter. Interestingly, in a sir4 deletion strain, repression of CHA1 is partly lost and activator-independent remodeling of nuc-1 is observed. We propose a model for CHA1 activation based on promoter remodeling through interactions of Cha4p with chromatin components other than basal factors and associated proteins.

KW - Chromatin

KW - DNA-Binding Proteins

KW - Fungal Proteins

KW - Genes, Fungal

KW - L-Serine Dehydratase

KW - Mutation

KW - Nucleosomes

KW - Promoter Regions, Genetic

KW - RNA Polymerase II

KW - Saccharomyces cerevisiae

KW - Saccharomyces cerevisiae Proteins

KW - Serine

KW - Silent Information Regulator Proteins, Saccharomyces cerevisiae

KW - TATA Box

KW - TATA-Box Binding Protein

KW - Threonine Dehydratase

KW - Trans-Activators

KW - Transcription Factors

U2 - 10.1093/emboj/17.20.6028

DO - 10.1093/emboj/17.20.6028

M3 - Journal article

C2 - 9774346

VL - 17

SP - 6028

EP - 6038

JO - E M B O Journal

JF - E M B O Journal

SN - 0261-4189

IS - 20

ER -