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Current Genetics

, Volume 33, Issue 1, pp 46–51 | Cite as

Allele-specific expression of the Mgi– phenotype on disruption of the F1-ATPase delta-subunit gene in Kluyveromyces lactis

  • P. M. Hansbro
  • Xin Jie Chen
  • G. D. Clark-Walker
ORIGINAL PAPER

Abstract

Kluyveromyces lactis is a petite-negative yeast that does not form viable mitochondrial genome-deletion mutants (petites) when treated with DNA-targeting drugs. Loss of mtDNA is lethal for this yeast but mutations at three loci termed MGI, for mitochondrial genome integrity, can suppress this lethality. The three loci encode the α-, β- and γ-subunits of mitochondrial F1-ATPase. In this study we report the isolation and characterization of the KlATPδ gene encoding the δ-subunit of F1-ATPase. The deduced protein contains 158 amino acids showing 72% identity to the protein from Saccharomyces cerevisiae and a putative mitochondrial targeting sequence of 23 amino acids. Disruption of the gene causes cells to become respiratory deficient while the introduction of ATPδ from S. cerevisiae restores growth on glycerol. Cells with a disrupted ATPδ gene, like strains with disruptions of α-, β- and γ-F1-subunits, do not produce petite mutants when treated with ethidium bromide. However, unlike strains with disruptions in the three largest F1-subunits, disruption of ATPδ in the presence of some mgi alleles does not abolish the Mgi phenotype. By contrast, elimination of ATPδ in other mgi strains removes resistance to ethidium bromide and ρ0 mutants are not formed. Hence the ATPδ subunit of F1-ATPase, while not mandatory for a Mgi phenotype, aids some mgi alleles in suppressing ρ0 lethality.

Key wordsKluyveromyces lactis Mitochondrial genome integrity F1-ATPase δ-subunit gene ATPδ -disruption 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • P. M. Hansbro
    • 1
  • Xin Jie Chen
    • 1
  • G. D. Clark-Walker
    • 1
  1. 1.Molecular and Cellular Genetics Group, Research School of Biological Sciences, The Australian National University, PO Box 475, Canberra City, ACT, 2601, Australia, Fax No: +61-6-279 8294, e-mail: dcw@rsbs-central.anu.edu.auAU

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