Pleiotropic mutations in Saccharomyces cerevisiae affecting sterol uptake and metabolism.
Sterol uptake control mutants (upc-) have been isolated via ethylmethanesulfonate mutagenesis from wild-type Saccharomyces cerevisiae. These mutants are heme and sterol competent but possess the ability to accumulate exogenous sterol(s) under aerobic conditions. Previous studies demonstrate sterol uptake only in a hem-, erg- background; however, the Upc- strains described here are Hem+ and do not require exogenous sterol for growth. We were unable to obtain viable hem+, erg-, upc+ recombinants; such combinations appear to be lethal. Isolates of Upc mutants demonstrated different levels of sterol uptake, and sterol analysis revealed a broad phenotypic range with regard to amounts and accumulation of ergosterol and non-ergosterol sterols. Assays of acyl CoA: ergosterol acyltransferase and sterol ester hydrolase showed no apparent difference in activity between Upc mutants and the wild type.
Lewis
T L
TL
Department of Microbiology, North Carolina State University, Raleigh 27695.
Keesler
G A
GA
Fenner
G P
GP
Parks
L W
LW
D002784:Cholesterol / Q000378:metabolism; D002849:Chromatography, Gas; D004875:Ergosterol / Q000378:metabolism; D006418:Heme / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D013261:Sterols / Q000378:metabolism*
D013261:Sterols; D006418:Heme; D002784:Cholesterol; D004875:Ergosterol