Functional domains in introns: trans-acting and cis-acting regions of intron 4 of the cob gene.
We have sequenced the mutational changes in eight mutants in the open reading frame of intron 4 of the cob gene on yeast mitochondrial DNA. Three have a cis-acting splicing defect, while the other inactivate a trans-recessive intron domain that specifies a trans-acting splicing factor. From phenotypic evidence, including analyses of the allele-specific extra proteins, we have identified a protein (P27) encoded wholly within the intron that appears to be the intron 4 splicing factor (maturase). The evidence suggests that P27 is a secondary translation product resulting from the proteolytic cleavage of a larger precursor encoded by exon and intron sequences, but an alternative model, in which P27 is a primary translation product, has not been ruled out.
D000595:Amino Acid Sequence; D001483:Base Sequence; D004272:DNA, Mitochondrial / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics; D005796:Genes; D009154:Mutation; D010641:Phenotype; D012323:RNA Processing, Post-Transcriptional; D012326:RNA Splicing; D012441:Saccharomyces cerevisiae / Q000235:genetics*
D004272:DNA, Mitochondrial; D005656:Fungal Proteins