A gene bank of a yeast wild type DNA in the high copy number vector YEp 13 was screened for recombinant plasmids which suppress the mitochondrial RNA splice defect exerted by mutant M1301, a −1 by deletion in the first intron of the mitochondrial COB gene (bIl). A total of 17 recombinant plasmids with similar suppressor activity were found. Restriction mapping and cross-hybridization of the inserts revealed that these 17 plasmids contain three different inserts, all lacking any extended sequence homology. Each of the inserts, when present in high copy number, has a similar suppressor activity: high in the presence of mutation M1301 in bll, a group II intron, and low but significant with the presence of few mutants in bI2 and bI3 of the COB gene, both of which are group I introns.
Suppression by high copy number RNA splicing Yeast mitochondria