Regulation of yeast mating-type interconversion: feedback control of HO gene expression by the mating-type locus.
AUTOR(ES)
Jensen, R
RESUMO
The ultimate product of yeast mating-type interconversion is a stable a/alpha diploid cell. A haploid cell carrying the HO gene gives rise to a diploid cell in a two-step process: first, the cell switches mating type as a result of genetic rearrangement (cassette substitution) catalyzed by HO; then, cells of opposite type mate to form a/alpha diploids. Mating-type interconversion does not occur in a/alpha diploids despite the presence of the HO gene. We have identified a plasmid carrying the HO gene by screening a yeast clone bank (constructed in vector YEp13) for plasmids that allow mating-type switching by ho cells. The yeast segment responsible for mating-type interconversion integrates by homology at the ho locus, thus confirming that it carries HO. Using the HO gene as a probe, we find that strains with an active mating-type interconversion system produce HO RNA, whereas a/alpha HO/HO cells do not and that this inhibition requires products of both the MATa1 and MATa2 genes. Thus, mating-type interconversion does not occur in a/alpha HO/HO cells because the HO gene product is not synthesized. These results demonstrate the following: (i) The mating-type locus, proposed on genetic grounds to be a regulatory locus, controls expression of an unlinked gene (HO) at the level of RNA production. (ii) The HO gene is under negative feedback control: its expression is inhibited after successful completion of diploidization (formation of a/alpha diploids).
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=393968Documentos Relacionados
- Control of STA1 gene expression by the mating-type locus in yeasts.
- Regulation by the yeast mating-type locus of STE12, a gene required for cell-type-specific expression.
- Regulation of Mating and Meiosis in Yeast by the Mating-Type Region
- The yeast ARD1 gene product is required for repression of cryptic mating-type information at the HML locus.
- Directionality of Fission Yeast Mating-Type Interconversion Is Controlled by the Location of the Donor Loci