F. Parviz et al., TRANSCRIPTIONAL REGULATION OF CLN3 EXPRESSION BY GLUCOSE IN SACCHAROMYCES-CEREVISIAE, Journal of bacteriology, 180(17), 1998, pp. 4508-4515
In Saccharomyces cerevisiae, the transition from the G(1) phase of the
mitotic cycle into S phase is controlled by a set of G(1) cyclins tha
t regulate the activity of the protein kinase encoded by CDC28. Yeast
cells regulate progress through the G(1)/S boundary in response to nut
rients, moving quickly through G(1) in glucose medium and more slowly
in poorer medium. We have examined connections between glucose and the
level of the message encoding Cln3, a G(1) cyclin. We found that gluc
ose positively regulates CLN3 mRNA levels through a set of repeated AA
GAAAAA (A(2)GA(5)) elements within the CLN3 promoter. Mutations in the
se sequences reduce both transcriptional activation and specific inter
action between CLN3 promoter elements and proteins in yeast extracts.
Creation of five point mutations, replacing the G's within these repea
ts with T's, in the CLN3 promoter substantially reduces CLN3 expressio
n in glucose medium and inhibits the ability of the cells to maintain
a constant size when shifted into glucose.