Mutation in the beta subunit of F ATPase allows Kluyveromyces lactis to survive the disruption of the KlPGS1 gene.
The petite-negative yeast Kluyveromyces lactis does not tolerate the loss of phosphatidylglycerol (PG). We demonstrate that the lethality of PG loss is suppressed in strains carrying a mutation in the beta subunit of F(1) ATPase (mgi1-1). Phenotypic characterization shows that the strain lacking the phosphatidylglycerolphosphate synthase gene (KlPGS1) is able to grow only on glucose, but significantly more slowly and to substantially lower densities than the parental mgi1-1 strain. In addition, oxygen consumption in the DeltaKlpgs1 strain is <1% of the parental strain. Western blot analysis of mitochondrial membrane proteins shows that the amounts of some proteins are substantially decreased or even not detectable in this mutant. However, overexpression of the KlPGS1 gene under the inducible GAL1 promoter does not restore the ability of DeltaKlpgs1 cells to grow on galactose, indicating the presence of some other mutations and/or deletions in genes involved in oxidative phosphorylation. We also demonstrate that DeltaKlpgs1 cells do not spontaneously lose mtDNA, but are able to survive its loss after ethidium bromide mutagenesis. Deletion of the cardiolipin synthase gene (KlCLS1) in mgi1-1 has only a minimal effect on mitochondrial physiology, and additional experiments show that this deletion is also viable in wild-type K. lactis.
Laboratory of Molecular Biology, Cancer Research Institute, Slovak Academy of Sciences, Bratislava, Slovakia.
Mária
M
Patrásová
Daniela
D
Kost'anová-Poliaková
Mária
M
Simocková
L'udmila
L
Sabová
D015153:Blotting, Western; D003470:Culture Media / Q000737:chemistry; D005690:Galactose / Q000378:metabolism; D017353:Gene Deletion; D020043:Genes, Essential; D007716:Kluyveromyces / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D050296:Microbial Viability; D051336:Mitochondrial Membranes / Q000737:chemistry; D010100:Oxygen / Q000378:metabolism; D010715:Phosphatidylglycerols / Q000378:metabolism; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000235:genetics* / Q000378:metabolism*; D017855:Transferases (Other Substituted Phosphate Groups) / Q000235:genetics*
D003470:Culture Media; D010715:Phosphatidylglycerols; D021122:Protein Subunits; D017855:Transferases (Other Substituted Phosphate Groups); C020676:CDP-diacylglycerol-glycerol-3-phosphate 3-phosphatidyltransferase; D006180:Proton-Translocating ATPases; D010100:Oxygen; D005690:Galactose