C25, an essential RNA polymerase III subunit related to the RNA polymerase II subunit RPB7

Mol Cell Biol. 1994 Sep;14(9):6164-70. doi: 10.1128/mcb.14.9.6164-6170.1994.


We identified a partially sequenced Saccharomyces cerevisiae gene which encodes a protein related to the S. cerevisiae RNA polymerase II subunit, RPB7. Several lines of evidence suggest that this related gene, YKL1, encodes the RNA polymerase III subunit C25. C25, like RPB7, is present in submolar ratios, easily dissociates from the enzyme, is essential for cell growth and viability, but is not required in certain transcription assays in vitro. YKL1 has ABF-1 and PAC upstream sequences often present in RNA polymerase subunit genes. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis mobility of the YKL1 gene product is equivalent to that of the RNA polymerase III subunit C25. Finally, a C25 conditional mutant grown at the nonpermissive temperature synthesizes tRNA at reduced rates relative to 5.8S rRNA, a hallmark of all characterized RNA polymerase III mutants.

Publication types

  • Comparative Study

MeSH terms

  • Amino Acid Sequence
  • Archaea / genetics
  • Gene Expression Regulation, Fungal
  • Genes, Fungal*
  • Molecular Sequence Data
  • Mutagenesis, Insertional
  • Promoter Regions, Genetic
  • RNA Polymerase II / chemistry
  • RNA Polymerase III / chemistry
  • RNA Polymerase III / genetics*
  • RNA Polymerase III / metabolism
  • RNA, Messenger / genetics
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae Proteins / chemistry*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Transcription, Genetic


  • RNA, Messenger
  • Saccharomyces cerevisiae Proteins
  • C25 protein, S cerevisiae
  • RNA Polymerase II
  • RNA Polymerase III

Associated data

  • GENBANK/U11048
  • GENBANK/X75411