Multiple elements regulate expression of the cell cycle-regulated thymidylate synthase gene of Saccharomyces cerevisiae

Expression of the thymidylate synthase gene (TMPI) of Saccharomyces cerevisiae increases during the late G1 phase of the cell cycle. Using a series of gene fusions, which have placed the Escherichia coli lacZ gene under transcriptional and translational control of different portions of the TMPI gene, we have demonstrated the existence of three different regions which are important for expression. One of these regions, which was localized to within 270 base pairs of the translation start codon, is involved in the periodic expression of TMPI transcript. A second region, the deletion of which resulted in reduced levels of TMPI expression, is at least partially encoded by DNA sequences between 270 and 377 base pairs upstream of the translation start codon. A third region, located within the N-terminal 112 codons of the TMPI gene, apparently encodes information involved in a post-translational control mechanism.