Calcium-sensitive cls4 mutant of Saccharomyces cerevisiae with a defect in bud formation

Abstract

A calcium-sensitive cls4 mutant of Saccharomyces cerevisiae ceased dividing in the presence of 100 mM CaC12, producing large, round, unbudded cells. Since its DNA replication and nuclear division still continued after interruption of normal budding, the cls4 mutant had a defect in bud formation in Ca2+-rich medium. Its calcium content and calcium uptake activity were the same as those of the wild-type strain, suggesting that the primary defect of the mutation was not in a Ca2+ transport system. Genetic analysis showed that the cls4 mutation did not complement the cdc24-1 mutation, which is known to be a temperature-sensitive mutation affecting bud formation and localized cell surface growth at a restrictive temperature. Moreover, cls4 was tightly linked to cdc24, and a yeast 3.4-kilobase-pair DNA fragment carrying both the CLS4 and CDC24 genes was obtained. These results suggest that the cls4 mutation is allelic to the cdc24 mutation. Thus, Ca2+ ion seems to control bud formation and bud-localized cell surface growth.

Molecular Cloning of a Gene,DHS1, Which Complements a Drug-hypersensitive Mutation of the YeastSaccharomyces cerevisiae

“…This library was constructed by inserting Sau3AI fragments of A5-8-lA (MATa, leuI) chromosomal DNA in the BamBI site of a centromere vector YCpG 11. 19) Chemicals and enzymes. N-Methyl-N'-nitro-N-nitrosoguanidine and antibiotics were purchased from Sigma Chemical Co. (St. Louis, U.S.A.).…”

Cell polarization directed by extracellular cues in yeast.

“…A localized elevation in intracellular Ca2" levels could cause organization of the cytoskeleton in the proper place by activating polarity-establishment gene products. Sequence analysis and the isolation of calcium-sensitive alleles suggest that Cdc24 protein may bind calcium (Ohya et al, 1986;Miyamoto et al, 1987). A yeast phospholipase C has recently been identified (Payne and Fitzgerald-Hayes, 1993), but mutants in the phospholipase C gene were not reported to display any defects in mating or shmooing.…”

Purification and biochemical properties of calmodulin from Saccharomyces cerevisiae

“…Since the CDC3I product was found specifically in the spindle pole body, Ca2+ seems to play some important role in spindle duplication. Although the terminal phenotypes of several Ca2+-mutants strongly suggested the crucial roles of Ca2+ ion the yeast cell cycle [7][8][9]111, the biochemical properties of calmodulin and other Ca2 +-binding proteins are only poorly understood.…”