ERG3/YLR056W Summary Help

Standard Name ERG3 1
Systematic Name YLR056W
Alias SYR1 , PSO6 2
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; mutants are viable, but cannot grow on non-fermentable carbon sources; substrate of the HRD ubiquitin ligase (1, 3, 4, 5, 6 and see Summary Paragraph)
Name Description ERGosterol biosynthesis 1
Chromosomal Location
ChrXII:253861 to 254958 | ORF Map | GBrowse
Gene Ontology Annotations All ERG3 GO evidence and references
  View Computational GO annotations for ERG3
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 8 genes
Classical genetics
Large-scale survey
462 total interaction(s) for 349 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 5
  • Affinity Capture-RNA: 3
  • Affinity Capture-Western: 2
  • Co-purification: 1
  • PCA: 18

Genetic Interactions
  • Dosage Rescue: 2
  • Negative Genetic: 309
  • Phenotypic Enhancement: 10
  • Phenotypic Suppression: 4
  • Positive Genetic: 70
  • Synthetic Growth Defect: 20
  • Synthetic Lethality: 11
  • Synthetic Rescue: 7

Expression Summary
Length (a.a.) 365
Molecular Weight (Da) 42,730
Isoelectric Point (pI) 7.73
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrXII:253861 to 254958 | ORF Map | GBrowse
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..1098 253861..254958 2011-02-03 1996-07-31
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | E.C. | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000004046

ERG3 encodes C-5 sterol desaturase, which catalyzes the introduction of a C-5(6) double bond into episterol, a precursor in ergosterol biosynthesis (1, 5, 3, 4). Cells lacking ERG3 are viable, but cannot grow on non-fermentable carbon sources, and some erg3 null strains are cold sensitive (1, 7, 8). Mutations in ERG3 alter sensitivity to a wide variety of drugs (9, 10, 11, 12). A mutation in ERG3 can suppress the erg11 null phenotype (13), and the erg3 erg11 double mutant is resistant to fenpropimorph (14). Mutations in genes encoding other sterol biosynthetic enzymes cause increased expression of ERG3 (15, 16). Expression of ERG9, which encodes farnesyl-diphosphate farnesyl transferase, is increased in erg3 mutants (17).

C-5 sterol desaturases have been identified in numerous organisms; homologs from Candida albicans, Arabidopsis, Nicotiana tabacum, and human can complements the erg3 null phenotype (18, 19, 20).

Last updated: 2000-09-06 Contact SGD

References cited on this page View Complete Literature Guide for ERG3
1) Arthington BA, et al.  (1991) Cloning, disruption and sequence of the gene encoding yeast C-5 sterol desaturase. Gene 102(1):39-44
2) Brendel M and Henriques JA  (2001) The pso mutants of Saccharomyces cerevisiae comprise two groups: one deficient in DNA repair and another with altered mutagen metabolism. Mutat Res 489(1):79-96
3) Lees ND, et al.  (1995) Cloning of the late genes in the ergosterol biosynthetic pathway of Saccharomyces cerevisiae--a review. Lipids 30(3):221-6
4) Parks LW, et al.  (1995) Biochemical and physiological effects of sterol alterations in yeast--a review. Lipids 30(3):227-30
5) Paltauf F, et al.  (1992) "Regulation and compartmentalization of lipid synthesis in yeast." Pp. 415-500 in The Molecular and Cellular Biology of the Yeast Saccharomyces: Gene Expression, edited by Jones EW, Pringle JR and Broach JR. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory Press
6) Jaenicke LA, et al.  (2011) Yos9p assists in the degradation of certain nonglycosylated proteins from the endoplasmic reticulum. Mol Biol Cell 22(16):2937-45
7) Smith SJ and Parks LW  (1993) The ERG3 gene in Saccharomyces cerevisiae is required for the utilization of respiratory substrates and in heme-deficient cells. Yeast 9(11):1177-87
8) Hemmi K, et al.  (1995) The physiological roles of membrane ergosterol as revealed by the phenotypes of syr1/erg3 null mutant of Saccharomyces cerevisiae. Biosci Biotechnol Biochem 59(3):482-6
9) Watson PF, et al.  (1988) Isolation and analysis of ketoconazole resistant mutants of Saccharomyces cerevisiae. J Med Vet Mycol 26(3):153-62
10) Taguchi N, et al.  (1994) Identification and analysis of the Saccharomyces cerevisiae SYR1 gene reveals that ergosterol is involved in the action of syringomycin. Microbiology 140 ( Pt 2)():353-9
11) Prendergast JA, et al.  (1995) Mutations sensitizing yeast cells to the start inhibitor nalidixic acid. Yeast 11(6):537-47
12) Schmidt CL, et al.  (1999) Allelism of Saccharomyces cerevisiae genes PSO6, involved in survival after 3-CPs+UVA induced damage, and ERG3, encoding the enzyme sterol C-5 desaturase. Yeast 15(14):1503-10
13) Bard M, et al.  (1993) Sterol synthesis and viability of erg11 (cytochrome P450 lanosterol demethylase) mutations in Saccharomyces cerevisiae and Candida albicans. Lipids 28(11):963-7
14) Lorenz RT and Parks LW  (1991) Physiological effects of fenpropimorph on wild-type Saccharomyces cerevisiae and fenpropimorph-resistant mutants. Antimicrob Agents Chemother 35(8):1532-7
15) Arthington-Skaggs BA, et al.  (1996) Positive and negative regulation of a sterol biosynthetic gene (ERG3) in the post-squalene portion of the yeast ergosterol pathway. FEBS Lett 392(2):161-5
16) Smith SJ, et al.  (1996) Transcriptional regulation by ergosterol in the yeast Saccharomyces cerevisiae. Mol Cell Biol 16(10):5427-32
17) Kennedy MA, et al.  (1999) Transcriptional regulation of the squalene synthase gene (ERG9) in the yeast Saccharomyces cerevisiae. Biochim Biophys Acta 1445(1):110-22
18) Gachotte D, et al.  (1996) Isolation and characterization of an Arabidopsis thaliana cDNA encoding a delta 7-sterol-C-5-desaturase by functional complementation of a defective yeast mutant. Plant J 9(3):391-8
19) Husselstein T, et al.  (1999) Delta7-sterol-C5-desaturase: molecular characterization and functional expression of wild-type and mutant alleles. Plant Mol Biol 39(5):891-906
20) Miyazaki Y, et al.  (1999) Cloning, sequencing, expression and allelic sequence diversity of ERG3 (C-5 sterol desaturase gene) in Candida albicans. Gene 236(1):43-51