ERG3 / YLR056W Overview


Standard Name
ERG3 1
Systematic Name
YLR056W
SGD ID
SGD:S000004046
Aliases
PSO6 22 , SYR1
Feature Type
ORF , Verified
Description
C-5 sterol desaturase; glycoprotein that catalyzes the introduction of a C-5(6) double bond into episterol, a precursor in ergosterol biosynthesis; transcriptionally down-regulated when ergosterol is in excess; mutants are viable, but cannot grow on non-fermentable carbon sources; substrate of HRD ubiquitin ligase; mutation is functionally complemented by human SC5D 1 2 3 4 5 6
Name Description
ERGosterol biosynthesis 1
Comparative Info
Sequence Details

Sequence

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

Protein

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.)
365
Mol. Weight (Da)
42730.6
Isoelectric Point
7.79
Median Abundance (molecules/cell)
6462 +/- 3482
Half-life (hr)
2.1

Alleles

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.


View all ERG3 alleles in SGD search

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.


Summary
C-5 sterol desaturase, catalyzes formation of C-5(6) double bond in episterol that yields 5,7,24(28)-ergostatrienol in third to last step of ergosterol biosynthesis pathway; integral to endoplasmic reticulum membrane

View computational annotations

Molecular Function

Manually Curated

Biological Process

Manually Curated

Cellular Component

Manually Curated

Pathways


Phenotype Details

Phenotype

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.


Summary
Non-essential gene; null mutant fails to synthesize ergosterol and cannot grow on nonfermentable carbon sources; null mutant exhibits increased resistance to azole antifungal drugs and decreased resistance to various other drugs; null mutant has reduced competitive fitness in a large-scale study
Interaction Details

Interaction

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.


2042 total interactions for 1144 unique genes

Physical Interactions

  • Affinity Capture-MS: 25
  • Affinity Capture-RNA: 6
  • Affinity Capture-Western: 2
  • PCA: 18
  • Proximity Label-MS: 1

Genetic Interactions

  • Dosage Growth Defect: 1
  • Dosage Rescue: 2
  • Negative Genetic: 1410
  • Phenotypic Enhancement: 12
  • Phenotypic Suppression: 19
  • Positive Genetic: 502
  • Synthetic Growth Defect: 24
  • Synthetic Lethality: 11
  • Synthetic Rescue: 9
Regulation Details

Regulation

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.


Summary
ERG3 encodes a C-5 sterol desaturase that participates with another desaturase Erg5p and a reductase Erg4p in the final step of ergosterol biosynthesis, the conversion of episterol to ergosterol. Ergosterol, the major sterol in fungi and the equivalent of cholesterol in mammalian cells, is an essential component of the plasma membrane, necessary for membrane integrity, fluidity, and proper function of membrane proteins. The entire sterol biosynthetic pathway occurs primarily in the endoplasmic reticulum (ER) and requires almost 30 enzymes. Activities of these enzymes have to be tightly controlled to ensure sufficient supply but also to prevent an excess accumulation of free sterols, which leads to toxicity. This regulation involves multiple mechanisms at transcriptional, translational and post-translational levels. Since sterol biosynthesis requires oxygen, under low-oxygen conditions sterol levels become low, which triggers relocation of two transcription factors, Upc2p and Ecm22p, to the nucleus. The two proteins then recognize and bind sterol regulatory elements (SRE) in the promoters of sterol biosynthesis genes and activate their transcription. Independently, oxygen levels affect transcription of sterol biosynthesis genes through a heme-dependent transcription factor Hap1p and a transcriptional repressor Rox1p. An excess of sterols, on the other hand, stimulates the ER-associated protein degradation (ERAD) pathway to remove the HMG-CoA reductase Hmg1p/Hmg2p, which catalyzes an early rate-limiting step in sterol biosynthesis, thus leading to decreased sterol production. Additionally, other components of the ergosterol pathway are also targeted for degradation by ERAD components Doa10p, Ubc7p and Cdc48p, and by another ER-associated degradation system. Despite some similarities, there are significant differences in sterol biosynthesis and its regulation between fungal and mammalian cells, which has made ergosterol biosynthesis an attractive target for antifungal drugs. Erg11p is a target of widely used azole drugs, whereas Erg1p is a target for terbinafine. Mutations in these genes are a major cause of antifungal drug resistance.
Regulators
15
Targets
0
Expression Details

Expression

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: 2000-09-06

Literature Details

Literature

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.


Primary
95
Additional
159
Reviews
28

Resources