The cloning and characterization of the CDC50 gene family in Saccharomycescerevisiae

We have cloned a gene that complements the cold-sensitive growth of cdc50-1 mutant strain of Saccharomyces cerevisiae at 14 degreesC. The CDC50 gene w as found to be identical to YCR094w on chromosome III and contains 1173 nuc leotides encoding 391 amino acids, We found a missense mutation at the firs t initiation codon of cdc50-1. The disruption of the CDC50 gene revealed th at it is not essential for growth, but the disruptant caused the same cold- sensitive phenotype as cdr50-1, suggesting that the cdc50-1 is a null mutat ion resulted from the mutation in the first codon. The cdc50-1 mutant arres ts at START in G(1) phase at the non-permissive temperature. The CDC50 gene product has strong structural similarity to two other proteins in Saccharo myces cerevisiae encoded by YNR048w and YNL323w. The over-expression of eit her YNR048w or YNL323w suppressed the cdc50-1 mutant and the double disrupt ion of either CDC50 and YNR048w or CDC50 and YNL323w resulted in a severe s low-growth phenotype, We conclude that these three genes constitute a famil y with redundant function. We also found that the CDC39 gene was a multicop y suppressor of cdc50-1 mutation, suggesting that the CDC50 family is invol ved in regulation of transcription via CDC39. Copyright (C) 2000 John Wiley & Sons, Ltd.