MOLECULAR AND GENETIC-ANALYSIS OF THE SNF7 GENE IN SACCHAROMYCES-CEREVISIAE

Mutations in the SNF7 gene of Saccharomyces cerevisiae prevent full de repression of the SUC2 (invertase) gene in response to glucose limitat ion. We report the molecular cloning of the SNF7 gene by complementati on. Sequence analysis predicts that the gene product is a 27-kDa acidi c protein. Disruption of the chromosomal locus causes a fewfold decrea se in invertase derepression, a growth defect on raffinose, temperatur e-sensitive growth on glucose, and a sporulation defect in homozygous diploids. Genetic analysis of the interactions of the snf7 null mutati on with ssn6 and spt6/ssn20 suppressor mutations distinguished SNF7 fr om the SNF2, SNF5 and SNF6 genes. The snf7 mutation also behaved diffe rently from mutations in SNF1 and SNF4 in that snf7 ssn6 double mutant s displayed a synthetic phenotype of severe temperature sensitivity fo r growth. We also mapped SNF7 to the right arm of chromosome XII near the centromere.