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Kem mutations affect nuclear fusion in Saccharomyces cerevisiae.

ABSTRACT: We have identified mutations in three genes of Saccharomyces cerevisiae, KEM1, KEM2 and KEM3, that enhance the nuclear fusion defect of kar1-1 yeast during conjugation. The KEM1 and KEM3 genes are located on the left arm of chromosome VII. Kem mutations reduce nuclear fusion whether the kem and the kar1-1 mutations are in the same or in different parents (i.e., in both kem kar1-1 X wild-type and kem X kar 1-1 crosses). kem 1 X kem 1 crosses show a defect in nuclear fusion, but kem 1 X wild-type crosses do not. Mutant kem 1 strains are hypersensitive to benomyl, lose chromosomes at a rate 10-20-fold higher than KEM+ strains, and lose viability upon nitrogen starvation. In addition, kem 1/kem 1 diploids are unable to sporulate. Cells containing a kem 1 null allele grow very poorly, have an elongated rod-shape and are defective in spindle pole body duplication and/or separation. The KEM 1 gene, which is expressed as a 5.5-kb mRNA transcript, contains a 4.6-kb open reading frame encoding a 175-kD protein.

SUBMITTER: Kim J

PROVIDER: S-EPMC1204279 | biostudies-other | 1990 Dec

REPOSITORIES: biostudies-other

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kem mutations affect nuclear fusion in Saccharomyces cerevisiae.

Kim J J Ljungdahl P O PO Fink G R GR

Genetics 19901201 4

We have identified mutations in three genes of Saccharomyces cerevisiae, KEM1, KEM2 and KEM3, that enhance the nuclear fusion defect of kar1-1 yeast during conjugation. The KEM1 and KEM3 genes are located on the left arm of chromosome VII. Kem mutations reduce nuclear fusion whether the kem and the kar1-1 mutations are in the same or in different parents (i.e., in both kem kar1-1 X wild-type and kem X kar 1-1 crosses). kem 1 X kem 1 crosses show a defect in nuclear fusion, but kem 1 X wild-type ...[more]

PMID: 2076815

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