GENOMIC DISRUPTION OF 6 BUDDING YEAST GENES GIVES ONE DRASTIC EXAMPLEOF PHENOTYPE STRAIN-DEPENDENCE

Using PCR to construct disruption cassettes, null alleles of six genes have been created in Saccharomyces cerevisiae. In a FY1679 background , no defects were detected in any of the haploid deletion mutants with respect to growth, gross morphology, or mating. A diploid Fy1679-deri ved Delta ygl194c/Delta ygl194c homozygous disruptant displayed reduce d sporulation. In contrast to the lack of phenotypic consequences of D elta yol100w disruptions in the FY1679 background, in the CEN.PK2 stra in even a heterozygous disruption of the same gene caused striking eff ects, very slow vegetative growth and highly impaired sporulation. Tet rad analysis showed YOL100w to be an essential gene in this strain. A copy of the YGL194c or the YOL100w wild-type gene borne on a centromer ic episomal plasmid was introduced into a corresponding disruption mut ant strain, and in both cases was found to partially complement the de fects. (C) 1998 John Wiley & Sons, Ltd.