J. Biol. Chem., Vol. 260, Issue 6, 3235-3238, Mar, 1985
A mutation in yeast mitochondrial DNA results in a precise excision of the terminal intron of the cytochrome b gene
J Hill, P McGraw and A Tzagoloff
The yeast nuclear gene CBP2 was previously proposed to code for a protein
necessary for processing of the terminal intron in the cytochrome b
pre-mRNA (McGraw, P., and Tzagoloff, A. (1983) J. Biol. Chem. 258,
9459-9468). In the present study we describe a mitochondrial mutation
capable of suppressing the respiratory deficiency of cbp2 mutants. The
mitochondrial suppressor mutation has been shown to be the result of a
precise excision of the last intervening sequence from the cytochrome b
gene. Strains with the altered mitochondrial DNA have normal levels of
mature cytochrome b mRNA and of cytochrome b and exhibit wild type growth
on glycerol. These results confirm that CBP2 codes for a protein
specifically required for splicing of the cytochrome b intron and further
suggest that absence of the intervening sequence does not noticeably affect
the expression of respiratory function in mitochondria.