Characterization of yeast iso-1-cytochrome c mRNA.

The iso-1-cytochrome c mRNA has been identified by hybridization of a 32P probe prepared from a plasmid containing the iso-1-cytochrome c gene to RNA size-fractionated on agarose gels and transferred to paper. A hybridization band was visible with RNA prepared from wild type cells, but not with RNA prepared from an iso-1-cytochrome c deletion mutant. RNA prepared from cells containing a nonsense mutation in the iso-1-cytochrome c gene showed reduced levels of hybridization. The RNA that hybridized to the probe was 700 +/- 50 nucleotides in length and was polyadenylated. The cellular levels of this RNA were repressed by glucose, and this repression was achieved within 5 min after glucose addition to a derepressed culture. No precursors of this RNA were detected in wild type cells or in an RNA1 mutant, temperature-sensitive for RNA metabolism. The length of the 3' noncoding region of this RNA was determined to be 200 +/- 25 nucleotides (excluding the poly(A) tail) and the 5' noncoding region was estimated to be about 120 nucleotides in length.