The yeast carboxyl-terminal repeat domain kinase CTDK-I is a divergent cyclin-cyclin-dependent kinase complex.

Journal Article (Journal Article)

Saccharomyces cerevisiae CTDK-I is a protein kinase complex that specifically and efficiently hyperphosphorylates the carboxyl-terminal repeat domain (CTD) of RNA polymerase II and is composed of three subunits of 58, 38, and 32 kDa. The kinase is essential in vivo for normal phosphorylation of the CTD and for normal growth and differentiation. We have now cloned the genes for the two smaller kinase subunits, CTK2 and CTK3, and found that they form a unique, divergent cyclin-cyclin-dependent kinase complex with the previously characterized largest subunit protein CTK1, a cyclin-dependent kinase homolog. The CTK2 gene encodes a cyclin-related protein with limited homology to cyclin C, while CTK3 shows no similarity to other known proteins. Copurification of the three gene products with each other and CTDK-I activity by means of conventional chromatography and antibody affinity columns has verified their participation in the complex in vitro. In addition, null mutations of each of the genes and all combinations thereof conferred very similar growth-impaired, cold-sensitive phenotypes, consistent with their involvement in the same function in vivo. These characterizations and the availability of all of the genes encoding CTDK-I and reagents derivable from them will facilitate investigations into CTD phosphorylation and its functional consequences both in vivo and in vitro.

Full Text

Duke Authors

Cited Authors

  • Sterner, DE; Lee, JM; Hardin, SE; Greenleaf, AL

Published Date

  • October 1995

Published In

Volume / Issue

  • 15 / 10

Start / End Page

  • 5716 - 5724

PubMed ID

  • 7565723

Pubmed Central ID

  • PMC230822

International Standard Serial Number (ISSN)

  • 0270-7306

Digital Object Identifier (DOI)

  • 10.1128/MCB.15.10.5716


  • eng

Conference Location

  • United States