kem mutations affect nuclear fusion in Saccharomyces cerevisiae.
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.
Kim
J
J
Massachusetts Institute of Technology, Cambridge.
Ljungdahl
P O
PO
Fink
G R
GR
D000595:Amino Acid Sequence; D001483:Base Sequence; D001542:Benomyl / Q000494:pharmacology; D015152:Blotting, Northern; D002467:Cell Nucleus / Q000502:physiology; D003001:Cloning, Molecular; D003227:Conjugation, Genetic; D003433:Crosses, Genetic; D004171:Diploidy; D004352:Drug Resistance, Microbial / Q000235:genetics; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D009154:Mutation; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000502:physiology; D013172:Spores, Fungal; D014158:Transcription, Genetic
D001542:Benomyl