OLE1/YGL055W Summary Help

Standard Name OLE1 1, 2
Systematic Name YGL055W
Alias MDM2 3
Feature Type ORF, Verified
Description Delta(9) fatty acid desaturase; required for monounsaturated fatty acid synthesis and for normal distribution of mitochondria (4, 5 and see Summary Paragraph)
Name Description OLEic acid requiring 1
Chromosomal Location
ChrVII:398628 to 400160 | ORF Map | GBrowse
Genetic position: -37 cM
Gene Ontology Annotations All OLE1 GO evidence and references
  View Computational GO annotations for OLE1
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 16 genes
Classical genetics
reduction of function
Large-scale survey
reduction of function
156 total interaction(s) for 104 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 15
  • Affinity Capture-RNA: 4
  • Affinity Capture-Western: 3
  • Biochemical Activity: 3
  • PCA: 17
  • Protein-RNA: 1
  • Two-hybrid: 1

Genetic Interactions
  • Dosage Rescue: 7
  • Negative Genetic: 78
  • Phenotypic Enhancement: 1
  • Positive Genetic: 16
  • Synthetic Growth Defect: 7
  • Synthetic Lethality: 3

Expression Summary
Length (a.a.) 510
Molecular Weight (Da) 58,403
Isoelectric Point (pI) 9.71
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrVII:398628 to 400160 | ORF Map | GBrowse
Genetic position: -37 cM
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..1533 398628..400160 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 SGDIDS000003023

OLE1 encodes the sole S. cerevisiae Delta-9 fatty acid desaturase, an ER membrane protein required for the production of monounsaturated fatty acids. Because these fatty acids are critical components of cell membranes, the OLE1 gene is essential unless the media are supplemented with unsaturated fatty acids. The primary products of Ole1p are palmitoleic (16:1) and oleic (18:1) fatty acids, formed from palmitoyl (16:0) and stearoyl (18:0) CoA, respectively (1, 4, and reviewed in 6).

The Ole1p sequence is similar to homologs in rat and human (SCD1) over the majority of the protein, including a cluster of histidine residues that coordinate the binding of a diiron-oxo prosthetic group within the catalytic site (reviewed in 6). The rat and yeast proteins are similar enough that exogenously expressed rat protein can rescue an ole1 null mutant (4). However, Ole1p has an additional C-terminal, 113 amino acid extension (relative to the rat protein), which encodes a cytochrome b5-like domain not found in mammalian desaturases. In animal cells, cytochrome b5 is thought to be the electron donor for fatty acid desaturation. In contrast, the yeast cytochrome b5 (Cyb5) is dispensable for the synthesis of unsaturated fatty acids because Ole1p contains inherent electron donor activity. The rat protein is unable to rescue an ole1 cyb5 double mutant (7).

OLE1 is highly regulated at the levels of both transcription and mRNA stability (reviewed in 6 and 8). OLE1 transcription is decreased in response to high fatty acid levels (9, 10) and increased in response to low oxygen (11) and low temperature (12). Much of the transcriptional regulation is mediated by two homologous ER membrane-bound transcription factors, Spt23p and Mga2p. In response to stimuli, both Spt23p and Mga2p are activated by ubiquitin-dependent processing into their soluble forms, and then targeted to the nucleus (13, 14, 15). Independent of the transcriptional regulation, OLE1 mRNA is also stabilized under fatty acid free conditions and destabilized when fatty acids are added to the growth medium (16). Mga2p, but not Spt23p, contributes to the regulation of OLE1 mRNA stability (17).

Last updated: 2010-05-10 Contact SGD

References cited on this page View Complete Literature Guide for OLE1
1) Stukey JE, et al.  (1989) Isolation and characterization of OLE1, a gene affecting fatty acid desaturation from Saccharomyces cerevisiae. J Biol Chem 264(28):16537-44
2) Bard M  (1972) Biochemical and genetic aspects of nystatin resistance in saccharomyces cerevisiae. J Bacteriol 111(3):649-57
3) Stewart LC and Yaffe MP  (1991) A role for unsaturated fatty acids in mitochondrial movement and inheritance. J Cell Biol 115(5):1249-57
4) Stukey JE, et al.  (1990) The OLE1 gene of Saccharomyces cerevisiae encodes the delta 9 fatty acid desaturase and can be functionally replaced by the rat stearoyl-CoA desaturase gene. J Biol Chem 265(33):20144-9
5) McConnell SJ, et al.  (1990) Temperature-sensitive yeast mutants defective in mitochondrial inheritance. J Cell Biol 111(3):967-76
6) Martin CE, et al.  (2007) Regulation of long chain unsaturated fatty acid synthesis in yeast. Biochim Biophys Acta 1771(3):271-85
7) Mitchell AG and Martin CE  (1995) A novel cytochrome b5-like domain is linked to the carboxyl terminus of the Saccharomyces cerevisiae delta-9 fatty acid desaturase. J Biol Chem 270(50):29766-72
8) Aguilar PS and de Mendoza D  (2006) Control of fatty acid desaturation: a mechanism conserved from bacteria to humans. Mol Microbiol 62(6):1507-14
9) Bossie MA and Martin CE  (1989) Nutritional regulation of yeast delta-9 fatty acid desaturase activity. J Bacteriol 171(12):6409-13
10) McDonough VM, et al.  (1992) Specificity of unsaturated fatty acid-regulated expression of the Saccharomyces cerevisiae OLE1 gene. J Biol Chem 267(9):5931-6
11) Kwast KE, et al.  (1999) Oxygen sensing in yeast: evidence for the involvement of the respiratory chain in regulating the transcription of a subset of hypoxic genes. Proc Natl Acad Sci U S A 96(10):5446-51
12) Nakagawa Y, et al.  (2002) Mga2p is a putative sensor for low temperature and oxygen to induce OLE1 transcription in Saccharomyces cerevisiae. Biochem Biophys Res Commun 291(3):707-13
13) Zhang S, et al.  (1999) MGA2 or SPT23 is required for transcription of the delta9 fatty acid desaturase gene, OLE1, and nuclear membrane integrity in Saccharomyces cerevisiae. Genetics 151(2):473-83
14) Hoppe T, et al.  (2000) Activation of a membrane-bound transcription factor by regulated ubiquitin/proteasome-dependent processing. Cell 102(5):577-86
15) Chellappa R, et al.  (2001) The membrane proteins, Spt23p and Mga2p, play distinct roles in the activation of Saccharomyces cerevisiae OLE1 gene expression. Fatty acid-mediated regulation of Mga2p activity is independent of its proteolytic processing into a soluble transcription activator. J Biol Chem 276(47):43548-56
16) Gonzalez CI and Martin CE  (1996) Fatty acid-responsive control of mRNA stability. Unsaturated fatty acid-induced degradation of the Saccharomyces OLE1 transcript. J Biol Chem 271(42):25801-9
17) Kandasamy P, et al.  (2004) Regulation of unsaturated fatty acid biosynthesis in Saccharomyces: the endoplasmic reticulum membrane protein, Mga2p, a transcription activator of the OLE1 gene, regulates the stability of the OLE1 mRNA through exosome-mediated mechanisms. J Biol Chem 279(35):36586-92