SPT8 / YLR055C Overview

Standard Name
SPT8 1
Systematic Name
Feature Type
ORF , Verified
Subunit of the SAGA transcriptional regulatory complex; not present in SAGA-like complex SLIK/SALSA; required for SAGA-mediated inhibition at some promoters 2 3
Name Description
SuPpressor of Ty 1
Comparative Info
Sequence Details


The S. cerevisiae Reference Genome sequence is derived from laboratory strain S288C. Download DNA or protein sequence, view genomic context and coordinates. Click "Sequence Details" to view all sequence information for this locus, including that for other strains.

Protein Details


Basic sequence-derived (length, molecular weight, isoelectric point) and experimentally-determined (median abundance, median absolute deviation) protein information. Click "Protein Details" for further information about the protein such as half-life, abundance, domains, domains shared with other proteins, protein sequence retrieval for various strains, physico-chemical properties, protein modification sites, and external identifiers for the protein.

Length (a.a.)
Mol. Weight (Da)
Isoelectric Point
Median Abundance (molecules/cell)
2347 +/- 1255
Half-life (hr)


Curated mutant alleles for the specified gene, listed alphabetically. Click on the allele name to open the allele page. Click "SGD search" to view all alleles in search results. Click "YeastMine" to view all alleles in YeastMine.

View all SPT8 alleles in SGD search | YeastMine

Gene Ontology Details

Gene Ontology

GO Annotations consist of four mandatory components: a gene product, a term from one of the three Gene Ontology (GO) controlled vocabularies (Molecular Function, Biological Process, and Cellular Component), a reference, and an evidence code. SGD has manually curated and high-throughput GO Annotations, both derived from the literature, as well as computational, or predicted, annotations. Click "Gene Ontology Details" to view all GO information and evidence for this locus as well as biological processes it shares with other genes.

TBP-binding transcription coregulator involved in histone acetylation, chromatin organization, and both positive and negative regulation of transcription by RNA polymerase II; subunit of SAGA complex, localizes to nucleus

View computational annotations

Molecular Function

Manually Curated

Cellular Component

Manually Curated


Macromolecular complex annotations are imported from the Complex Portal. These annotations have been derived from physical molecular interaction evidence extracted from the literature and cross-referenced in the entry, or by curator inference from information on homologs in closely related species or by inference from scientific background.

Phenotype Details


Phenotype annotations for a gene are curated single mutant phenotypes that require an observable (e.g., "cell shape"), a qualifier (e.g., "abnormal"), a mutant type (e.g., null), strain background, and a reference. In addition, annotations are classified as classical genetics or high-throughput (e.g., large scale survey, systematic mutation set). Whenever possible, allele information and additional details are provided. Click "Phenotype Details" to view all phenotype annotations and evidence for this locus as well as phenotypes it shares with other genes.

Non-essential gene; null mutants have abnormal vacuolar morphology, enhanced respiration and caffeine tolerance, impaired sporulation, are sensitive to DNA-damaging agents, heat, osmotic stress, dessication, and are auxotrophic for myo-inositol; overexpression slows growth
Interaction Details


Interaction annotations are curated by BioGRID and include physical or genetic interactions observed between at least two genes. An interaction annotation is composed of the interaction type, name of the interactor, assay type (e.g., Two-Hybrid), annotation type (e.g., manual or high-throughput), and a reference, as well as other experimental details. Click "Interaction Details" to view all interaction annotations and evidence for this locus, including an interaction visualization.

881 total interactions for 426 unique genes

Physical Interactions

  • Affinity Capture-MS: 205
  • Affinity Capture-RNA: 10
  • Affinity Capture-Western: 25
  • Biochemical Activity: 2
  • Co-localization: 1
  • Co-purification: 20
  • PCA: 1
  • Reconstituted Complex: 23
  • Two-hybrid: 1

Genetic Interactions

  • Dosage Lethality: 1
  • Dosage Rescue: 2
  • Negative Genetic: 276
  • Phenotypic Enhancement: 7
  • Phenotypic Suppression: 4
  • Positive Genetic: 51
  • Synthetic Growth Defect: 130
  • Synthetic Lethality: 103
  • Synthetic Rescue: 19
Regulation Details


The number of putative Regulators (genes that regulate it) and Targets (genes it regulates) for the given locus, based on experimental evidence. This evidence includes data generated through high-throughput techniques. Click "Regulation Details" to view all regulation annotations, shared GO enrichment among regulation Targets, and a regulator/target diagram for the locus.

SPT8 encodes a subunit of SAGA, a histone acetyltransferase and transcriptional coactivator complex that regulates transcription of a subset of RNA polymerase II-dependent genes. At some SAGA-dependent promoters, Spt8p helps to mediate recruitment of the general transcription machinery and thus positively regulates transcription. In addition, Spt8p negatively affects basal expression of some promoters by preventing SAGA interaction with the transcription machinery. Spt8p, along with Spt3p, form one class of SAGA subunits whose role is to control the TATA box binding protein (TBP)-TATA interaction at the promoter. Evidence suggests that the positive and negative functions of Spt8p in transcription are mediated through the general transcription factor TFIIA. Photocrosslinking studies of preinitiation complexes (PICs) indicate that Spt8p is in close proximity with TFIIA and TBP (Spt15p). Spt8p can interact with TBP and appears to compete with TFIIA for binding to TBP. Under conditions of basal transcription, this competition may prevent optimal expression, while under activated conditions, the competition is averted, possibly through a conformational change in Spt8p or TFIIA that enables them both to bind TBP and stimulate transcription.
Expression Details


Expression data are derived from records contained in the Gene Expression Omnibus (GEO), and are first log2 transformed and normalized. Referenced datasets may contain one or more condition(s), and as a result there may be a greater number of conditions than datasets represented in a single clickable histogram bar. The histogram division at 0.0 separates the down-regulated (green) conditions and datasets from those that are up-regulated (red). Click "Expression Details" to view all expression annotations and details for this locus, including a visualization of genes that share a similar expression pattern.

Summary Paragraph

A summary of the locus, written by SGD Biocurators following a thorough review of the literature. Links to gene names and curated GO terms are included within the Summary Paragraphs.

Last Updated: 2006-06-30

Literature Details


All manually curated literature for the specified gene, organized into topics according to their relevance to the gene (Primary Literature, Additional Literature, or Review). Click "Literature Details" to view all literature information for this locus, including shared literature between genes.