TRANSCRIPTIONAL CONTROL OF YEAST PLASMA-MEMBRANE H-ATPASE BY GLUCOSE - CLONING AND CHARACTERIZATION OF A NEW GENE INVOLVED IN THIS REGULATION()

The expression of the ATPase gene (PMA1) is regulated by glucose (Rao, R., Drummond-Barbosa, D., and Slayman, C. W. (1993) Yeast 9, 1075-108 4) and by the TUF/RAP1/GRF1 transcription factor (Capieaux, E., Vignai s, M.-L., Sentenac, A., and Goffeau, A (1989) J. Biol. Chem. 264, 7437 -7446). In this work, we describe the isolation of mutations on seven genes that affect the levels of ATPase. One of these genes (APA1) was cloned by complementation and shown to encode a protein with six putat ive transmembrane stretches. Expression of APA1 gene is regulated by t he carbon source and requires the protein GCR1. Deletion of APA1 cause s a defective regulation of the PMA1 expression by glucose but has not noticeable effect on the expression of other TUF-regulated genes. Nev ertheless the expression of glucose-repressible HXT3 and SNF3 genes is significantly reduced. These results suggest a model in which APA1 ac ts on a glucose-signaling pathway that controls the expression of seve ral genes that are transcriptionally regulated by glucose.