MSS11, a novel yeast gene involved in the regulation of starch metabolism

• Published in: Current genetics 1997-10, Vol.32 (4), p.260-266
• Main Authors: Webber, A.L, Lambrechts, M.G, Pretorius, I.S
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; amino acid sequences; carbohydrate metabolism; Chromosome Mapping; Chromosomes, Fungal; cloning; Cloning, Molecular; enzyme activity; Escherichia coli; Fungal Proteins - biosynthesis; Fungal Proteins - genetics; Fungal Proteins - metabolism; Gene Deletion; Gene Dosage; gene expression; Gene Expression Regulation, Fungal; Genotype; glucan 1,4-alpha-glucosidase; Glucan 1,4-alpha-Glucosidase - biosynthesis; Glucan 1,4-alpha-Glucosidase - genetics; growth; messenger RNA; Molecular Sequence Data; mss11 gene; nucleotide sequences; Plasmids; Recombinant Proteins - biosynthesis; Recombinant Proteins - chemistry; Recombinant Proteins - metabolism; regulator genes; Restriction Mapping; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins; Signal Transduction; sta2 gene; starch; Starch - metabolism; Transcription Factors; transcriptional activators
• ISSN: 0172-8083; 1432-0983
• DOI: 10.1007/s002940050275

Expression of the STA1-3 glucoamylase genes, responsible for starch degradation in Saccharomyces cerevisiae, is down regulated by the presence of STA10. In order to elucidate the role of STA10 in the regulation of the glucoamylase system, a multicopy genomic library was constructed and screened for genes that enhanced growth of a STA2-STA10 S. cerevisiae strain on starch media. This screen allowed us to clone and characterize a novel activator gene of STA2 (and by extrapolation, STA1 and STA3), designated MSS11. A strain transformed with multiple copies of MSS11 exhibits increased levels of STA2 mRNA and, consequently, increased glucoamylase activity. Deletion of MSS11, located on chromosome XIII, results in media-dependent absence of glucoamylase synthesis. MSS11 has not been cloned previously and the encoded protein, Mss11p, is not homologous to any other known protein. An outstanding feature of Mss11p is that the protein contains regions of 33 asparagine residues interrupted by only three serine residues, and 35 glutamine residues interrupted by a single histidine residue. Epistasis studies showed that deletion of MSS11 abolishes the activation of STA2 caused by the over-expression of MSS10, a previously identified gene. In turn, it was found that deletion of MSS10 still allows activation of STA2 by over-expression of MSS11. Mss11p therefore appears to be positioned below Mss10p in a signal transduction pathway.