Nucleotide sequence of the SAC2 gene of Saccharomyces cerevisiae

A temperature-sensitive mutation (act1-1) in the essential actin gene of Saccharomyces cerevisiae can be suppressed by mutations in the SAC2 gene. A cloned genomic DNA fragment that complements the cold-sensitive growth phenotype associated with such a suppressor mutation (sac2-1) was sequenced. The fragment contained an open reading frame that encodes a 641 amino acid predicted hydrophilic protein with a molecular weight of 74,445. No sequences with significant similarity to SAC2 were found in the GenBank and EMBL databases. A SAC2 disruption mutation was constructed which had phenotypes similar to the sac2-1 point mutation. A haploid SAC2 disruption strain failed to grow at low temperature and the disruption allele suppressed the temperature-sensitive act1-1 growth defect. The suppression phenotype was dependent on the strain background.