The mitochondrial genome of Schizosaccharomyces pombe

Summary The open reading frame of the first intron of the mitochondrial cox1 gene (cox1I1) was expressed in Escherichia coli. The putative intron-encoded protein stimulated the formation of intra-chromosomal lac⁺-recombinants about threefold. No stimulation was found when the reading frame was inserted in the opposite direction, or when it was interrupted by a deletion. The intronic open reading frame did not complement recA^– or recB^– mutants of E. coli. In S. pombe, elimination of this intron did not abolish homologous recombination in mitochondria. A possible role of the recombinase activity in yeast mitochondria will be discussed.