ISSN:
0749-503X
Keywords:
CLN1
;
CLN2
;
CLN3
;
G1 cyclins
;
stationary phase
;
WHI2
;
Life and Medical Sciences
;
Genetics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
Notes:
Wild-type cells of the budding yeast Saccharomyces cerevisiae arrest in G1 upon nutrient exhaustion. Cell cycle arrest requires the WHI2 gene since whi2 mutants continue to divide and become abnormally small as nutrients are depleted. Here we show that CLN1 and CLN2 transcript levels in a whi2 strain are higher during exponential growth, and persist longer upon starvation, than in an isogenic wild-type strain. In contrast to CLN1 and CLN2, CLN3 levels declined only at very high cell density and were unaffected by the whi2 mutation. Elevated CLN expression is sufficient to explain the whi2 phenotype since ectopic expression of CLN1 in a nutrient-depleted culture caused cells to continue dividing and interfered with the acquisition of heat resistance. These observations show that, either directly or indirectly, Whi2 negatively regulates G1 cyclin expression. Interestingly extremely high levels of Cln1 induced filamentous growth upon nutrient deprivation, suggesting a direct connection between G1 cyclin activity and morphological responses to poor nutrient conditions. © 1997 John Wiley & Sons, Ltd.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
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