THE SACCHAROMYCES-CEREVISIAE SPT14 GENE IS ESSENTIAL FOR NORMAL EXPRESSION OF THE YEAST TRANSPOSON, TY, AS WELL AS FOR EXPRESSION OF THE HIS4 GENE AND SEVERAL GENES IN THE MATING PATHWAY

To investigate the role of the trans-acting transcription factor encoded by the essential SPT14 (SPT = Suppressor of Ty insertion mutations) gene, we have cloned, mapped and sequenced the gene. From the analysis of the effect of spt14 mutations on expression of various genes, we conclude that the SPT14 product has an important role in activation of Ty transcription as well as in the regulation of other genes including HIS4 and several of the a- and alpha-specific mating type genes. Similarities in the phenotypes of spt14 and spt13 mutants (suppression of Ty insertion mutations but not delta-insertion mutations), lead to the suggestion that the SPT14 gene and the previously characterized SPT13/GAL11 gene might encode transcriptional regulators with related functions. Our current findings show that in contrast to SPT13/GAL11, which appears negatively to regulate Ty transcription, SPT14 plays a role in the activation of Ty transcription. Thus, despite the similarities in the suppression phenotype exhibited by spt13 and spt14 mutants, SPT13/GAL11 and SPT14 probably differ in their transcriptional roles.