The mitochondrial genome of the fission yeast Schizosaccharomyces pombe

Abstract

The Schizosaccharomyces pombe strain EF1 (CBS 356) is haploid, prototrophic, respiratory competent, and of homothallic mating type. From restriction enzyme analysis the length of the mitochondrial genome is 17.3 kilobase pairs, which is in good agreement with the value of 17.1 kilobase pairs determined by electron microscopy. The mitochondrial genome of strain EF1 is thus about 2.3 kilobase pairs shorter than that of strain ade7-50h- (about 19.4 kilobase pairs). A restriction map was constructed for 11 enzymes: For most, but not all of them, the pattern is nearly identical to that of strain ade7-50h-. The genes for the large ribosomal RNA, the subunits 1, 2, and 3 of cytochrome c oxidase, subunits 6 and 9 of ATP synthetase, and cytochrome b were localized by hybridization with mitochondrial DNA probes from Saccharomyces cerevisiae. The gene order was found to be the same in both yeast strains. From Southern hybridization of strain ade7-50h- with nick-translated mitochondrial DNA from strain EF1 it is evident that strain EF1 does not possess the intron, which is present in the cytochrome b gene of Schizosaccharomyces pombe strain ade7-50h-. Crosses between strain ade7-50h- and EF1 demonstrate that both the nuclear and the mitochondrial genomes are able to recombine. The mitochondrial genomes of 2 out of 30 independently isolated hybrids between the two strains are described as the result of recombination between the two parental mitochondrial genomes.

Intraspecific Diversity of Fission Yeast Mitochondrial Genomes

“…The reference S. pombe mitogenome (accession numbers NC_001326.1 and X54421.1) was from a Leupold-background strain with the genotype h − ade7-50 (Lang 1984; Zimmer et al. 1984).…”

“…No complete mitogenome sequences of any other S. pombe isolates have been reported thus far. Restriction fragment analysis and limited Sanger sequencing have indicated that presence–absence polymorphisms of mitochondrial introns are widespread among S. pombe isolates (Zimmer et al. 1984, 1987), but an accurate and thorough understanding of intraspecific mitogenomic variation of S. pombe is still lacking.…”