The RP031 gene of Saccharomyces cerevisiae encodes the largest subunit of RNA polymerase III

The 5′ end of the RNA transcript of the Saccharomyces cerevisiae RNA polymerase related gene, RP031, was localized on the RP031 locus using Northern analyses and primer extension experiments. The amino terminal protein sequence was determined for the largest (relative mass ~ 160 000) subunit polypeptide of S. cerevisiae RNA polymerase III. The N-terminal amino acid sequence of this polypeptide was shown to be identical to that predicted for a putative RP031 polypeptide initiated at the first ATG codon located 208–216 base pairs 3′ to the major RP031 mRNA start sites. The RP031 locus thus encodes the largest subunit of S. cerevisiae RNA polymerase III.