Regulation of the Saccharomyces cerevisiae WHI2 gene.

WHI2 mRNA levels were followed through the growth cycle in WHI2 mutant and wild-type cells of Saccharomyces cerevisiae. Levels were high during the first (glucose) phase of growth, and were reduced sharply during the second (ethanol) phase of growth. Transcript levels of the glycolytic genes PDC1 and PYK1 were also measured; they each showed a pattern similar to that of WHI2, whereas transcript levels of the CDC7 gene remained constant throughout the cycle, showing that a decrease in transcription is not a general feature of genes. These results make it unlikely that the WHI2 product acts as an inhibitor of cell proliferation which is activated upon carbon starvation. No difference was observed between the pattern of expression of mutant and wild-type strains, showing that the mutant phenotype was not the result of a change in regulation at the transcriptional level.