Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Mol Cell Biol. 1999 Jan;19(1):86-98.

Functional organization of the yeast SAGA complex: distinct components involved in structural integrity, nucleosome acetylation, and TATA-binding protein interaction.

Author information

  • 1The Wistar Institute, Philadelphia, Pennsylvania 19104, USA.

Abstract

SAGA, a recently described protein complex in Saccharomyces cerevisiae, is important for transcription in vivo and possesses histone acetylation function. Here we report both biochemical and genetic analyses of members of three classes of transcription regulatory factors contained within the SAGA complex. We demonstrate a correlation between the phenotypic severity of SAGA mutants and SAGA structural integrity. Specifically, null mutations in the Gcn5/Ada2/Ada3 or Spt3/Spt8 classes cause moderate phenotypes and subtle structural alterations, while mutations in a third subgroup, Spt7/Spt20, as well as Ada1, disrupt the complex and cause severe phenotypes. Interestingly, double mutants (gcn5Delta spt3Delta and gcn5Delta spt8Delta) causing loss of a member of each of the moderate classes have severe phenotypes, similar to spt7Delta, spt20Delta, or ada1Delta mutants. In addition, we have investigated biochemical functions suggested by the moderate phenotypic classes and find that first, normal nucleosomal acetylation by SAGA requires a specific domain of Gcn5, termed the bromodomain. Deletion of this domain also causes specific transcriptional defects at the HIS3 promoter in vivo. Second, SAGA interacts with TBP, the TATA-binding protein, and this interaction requires Spt8 in vitro. Overall, our data demonstrate that SAGA harbors multiple, distinct transcription-related functions, including direct TBP interaction and nucleosomal histone acetylation. Loss of either of these causes slight impairment in vivo, but loss of both is highly detrimental to growth and transcription.

PMID:
9858534
[PubMed - indexed for MEDLINE]
PMCID:
PMC83868
Free PMC Article

Images from this publication.See all images (8)Free text

FIG. 1
FIG. 2
FIG. 3
FIG. 4
FIG. 5
FIG. 6
FIG. 7
FIG. 8
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk