The a-factor pheromone of Saccharomyces cerevisiae is essential for mating.
The Saccharomyces cerevisiae pheromone a-factor is produced by a cells and interacts with alpha cells to cause cell cycle arrest and other physiological responses associated with mating. Two a-factor structural genes, MFA1 and MFA2, have been previously cloned with synthetic probes based on the a-factor amino acid sequence (A. Brake, C. Brenner, R. Najarian, P. Laybourn, and J. Merryweather, cited in M.-J. Gething [ed.], Protein transport and secretion, 1985). We have examined the function of these genes in a-factor production and mating by construction and analysis of chromosomal null mutations. mfa1 and mfa2 single mutants each exhibited approximately half the wild-type level of a-factor activity and were proficient in mating, whereas the mfa1 mfa2 double mutant produced no a-factor and was unable to mate. These results demonstrate that both genes are functional, that each gene makes an equivalent contribution to the a-factor activity and mating capacity of a cells, and that a-factor plays an essential role in mating. Strikingly, exogenous a-factor did not alleviate the mating defect of the double mutant, suggesting that an a cell must be producing a-factor to be an effective mating partner.
Michaelis
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Department of Biochemistry and Biophysics, University of California, San Francisco 94143-0448.
Herskowitz
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D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004271:DNA, Fungal / Q000235:genetics; D005786:Gene Expression Regulation; D005796:Genes; D005800:Genes, Fungal; D000072235:Mating Factor; D008969:Molecular Sequence Data; D009154:Mutation; D009693:Nucleic Acid Hybridization; D010452:Peptide Biosynthesis; D010455:Peptides / Q000235:genetics* / Q000502:physiology; D010675:Pheromones / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D010957:Plasmids; D012331:RNA, Fungal / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000502:physiology
D004271:DNA, Fungal; D010455:Peptides; D010675:Pheromones; D012331:RNA, Fungal; D000072235:Mating Factor