MOL1, a Saccharomyces cerevisiae gene that is highly expressed in early stationary phase during growth on molasses.

We have isolated a new Saccharomyces cerevisiae gene, MOL1, that is transiently expressed at high levels in the early stationary phase of batch cultures growing on industrial molasses medium. The DNA sequence of the MOL1 gene (for MOLasses-inducible) with its flanking regions was determined (EMBL accession number X61669). It encodes a polypeptide of M(r) 35 kDa that is closely related to stress-inducible proteins of similar size from two Fusarium species. Unlike ST135 of Fusarium, MOL1 is not induced by ethanol or heat shock. MOL1 expression is absent in rich (YP) medium, and only very low levels of expression are detectable in minimal (YNB) medium. The gene is not essential, and a MOL1 disruption strain showed no apparent phenotype under a variety of growth conditions. The 5' region of MOL1 contains the complete sequence previously determined for the SUF4 locus, encoding a tRNA-gly (UCC) gene, which has been mapped to chromosome VII.