Replication and preferential inheritance of hypersuppressive petite mitochondrial DNA.
Wild-type yeast mitochondrial DNA (mtDNA) is inherited biparentally, whereas mtDNA of hypersuppressive petite mutants is inherited uniparentally in crosses to strains with wild-type mtDNA. Genomes of hypersuppressive petites contain a conserved ori sequence that includes a promoter, but it is unclear whether the ori confers a segregation or replication advantage. Fluorescent in situ hybridization analysis of wild-type and petite mtDNAs in crosses reveals no preferential segregation of hypersuppressive petite mtDNA to first zygotic buds. We identify single-stranded DNA circles and RNA-primed DNA replication intermediates in hypersuppressive petite mtDNA that are absent from non-hypersuppressive petites. Mutating the promoter blocks hypersuppressiveness in crosses to wild-type strains and eliminates the distinctive replication intermediates. We propose that promoter-dependent RNA-primed replication accounts for the uniparental inheritance of hypersuppressive petite mtDNA.
MacAlpine
D M
DM
Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA.
Kolesar
J
J
Okamoto
K
K
Butow
R A
RA
Perlman
P S
PS
D004261:DNA Replication; D004270:DNA, Circular; D004271:DNA, Fungal / Q000096:biosynthesis*; D004272:DNA, Mitochondrial / Q000096:biosynthesis*; D004277:DNA, Single-Stranded; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D011401:Promoter Regions, Genetic; D018741:Replication Origin; D012441:Saccharomyces cerevisiae / Q000235:genetics; D014158:Transcription, Genetic
D004270:DNA, Circular; D004271:DNA, Fungal; D004272:DNA, Mitochondrial; D004277:DNA, Single-Stranded