HMRA2/YCR096C Summary Help

Standard Name HMRA2
Systematic Name YCR096C
Alias A2
Feature Type ORF, Verified|silenced_gene
Description Silenced copy of a2 at HMR; similarity to Alpha2p; required along with a1p for inhibiting expression of the HO endonuclease in a/alpha HO/HO diploid cells with an active mating-type interconversion system (1, 2 and see Summary Paragraph)
Name Description Hidden Mat Right A
Chromosomal Location
ChrIII:293538 to 293179 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Gene Ontology Annotations All HMRA2 GO evidence and references
  View Computational GO annotations for HMRA2
Molecular Function
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 4 genes
Large-scale survey
1 total interaction(s) for 1 unique genes/features.
Physical Interactions
  • Affinity Capture-RNA: 1

Expression Summary
Length (a.a.) 119
Molecular Weight (Da) 13,882
Isoelectric Point (pI) 10.75
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrIII:293538 to 293179 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
This feature is contained within: HMR
Last Update Coordinates: 2011-02-03 | Sequence: 1997-01-28
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..360 293538..293179 2011-02-03 1997-01-28
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000000692

a2 is one of two genes encoded by the a mating type cassette in S. cerevisiae. The mating type of S. cerevisiae is determined by the genetic composition of the MAT locus (3, 4, 2). Haploids of the a mating type express the genes a1 and a2 from the MAT locus while haploids of the alpha mating type express alpha1 and alpha2 from MAT (3, 4, 2). Some of the cells within a given colony are capable of switching mating type by changing the genetic composition of the MAT locus (5); more information on mating type switching can be found in the summary paragraph for MAT and references cited therein. Diploid cells are normally heterozygous (a/alpha) at the MAT locus (3, 4, 2).

The function of the a2 protein is unknown (2). One group has proposed that a2p in involved in the haploid-specific expression of STA1 in S. diastaticus (6), but another group showed that deletion of a2 has no detectable effect on STA1 expression (7). The a2 null also shows no growth, mating or sporulation defect (7).

Note: The maps and sequences within SGD reflect the fact that a MATalpha strain was used in the systematic sequencing project. Accordingly, there are two copies of the alpha1 and alpha2 genes; one pair (MATalpha1/YCR040W and MATalpha2/YCR039C) corresponds to the MAT locus, and the other (HMLalpha1/YCL066W and HMLalpha2/YCL067C) to the HML locus. There are ORFs assigned to the copies of a1 and a2 found at HMR (HMRa1/YCR097W) and (HMRa2/YCR096C); locus entries are included for MATa1 and MATa2 but they do not have ORFs associated with them. There are GenBank sequences available from all of the locus pages describing a1, a2, alpha1, and alpha2; the Genbank accession for the MATa cassette is V01313.

Last updated: 2000-08-15 Contact SGD

References cited on this page View Complete Literature Guide for HMRA2
1) Jensen R, et al.  (1983) Regulation of yeast mating-type interconversion: feedback control of HO gene expression by the mating-type locus. Proc Natl Acad Sci U S A 80(10):3035-9
2) Herskowitz I, et al.  (1992) "Mating-type determination and mating-type interconversion in Saccharomyces cerevisiae." Pp. 583-656 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
3) Herskowitz I  (1983) Cellular differentiation, cell lineages, and transposable genetic cassettes in yeast. Curr Top Dev Biol 18:1-14
4) Herskowitz I  (1989) A regulatory hierarchy for cell specialization in yeast. Nature 342(6251):749-57
5) Haber JE  (1998) Mating-type gene switching in Saccharomyces cerevisiae. Annu Rev Genet 32:561-99
6) Yamashita I, et al.  (1985) Control of STA1 gene expression by the mating-type locus in yeasts. J Bacteriol 164(2):769-73
7) Dranginis AM  (1989) Regulation of STA1 gene expression by MAT during the life cycle of Saccharomyces cerevisiae. Mol Cell Biol 9(9):3992-8
8) Badis G, et al.  (2008) A library of yeast transcription factor motifs reveals a widespread function for Rsc3 in targeting nucleosome exclusion at promoters. Mol Cell 32(6):878-87