Impairment of the TFIIH-associated CDK-activating kinase selectively affects cell cycle-regulated gene expression in fission yeast

Mol Biol Cell. 2005 Jun;16(6):2734-45. doi: 10.1091/mbc.e04-11-0982. Epub 2005 Apr 13.

Abstract

The fission yeast Mcs6-Mcs2-Pmh1 complex, homologous to metazoan Cdk7-cyclin H-Mat1, has dual functions in cell division and transcription: as a partially redundant cyclin-dependent kinase (CDK)-activating kinase (CAK) that phosphorylates the major cell cycle CDK, Cdc2, on Thr-167; and as the RNA polymerase (Pol) II carboxyl-terminal domain (CTD) kinase associated with transcription factor (TF) IIH. We analyzed conditional mutants of mcs6 and pmh1, which activate Cdc2 normally but cannot complete cell division at restrictive temperature and arrest with decreased CTD phosphorylation. Transcriptional profiling by microarray hybridization revealed only modest effects on global gene expression: a one-third reduction in a severe mcs6 mutant after prolonged incubation at 36 degrees C. In contrast, a small subset of transcripts ( approximately 5%) decreased by more than twofold after Mcs6 complex function was compromised. The signature of repressed genes overlapped significantly with those of cell separation mutants sep10 and sep15. Sep10, a component of the Pol II Mediator complex, becomes essential in mcs6 or pmh1 mutant backgrounds. Moreover, transcripts dependent on the forkhead transcription factor Sep1, which are expressed coordinately during mitosis, were repressed in Mcs6 complex mutants, and Mcs6 also interacts genetically with Sep1. Thus, the Mcs6 complex, a direct activator of Cdc2, also influences the cell cycle transcriptional program, possibly through its TFIIH-associated kinase function.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle / genetics
  • Cyclin-Dependent Kinase-Activating Kinase
  • Cyclin-Dependent Kinases / genetics
  • Cyclin-Dependent Kinases / metabolism*
  • Enzyme Activation
  • Gene Expression Profiling
  • Gene Expression Regulation, Fungal*
  • Genes, Fungal
  • Mutation
  • Oligonucleotide Array Sequence Analysis
  • Schizosaccharomyces / cytology
  • Schizosaccharomyces / enzymology*
  • Schizosaccharomyces / genetics
  • Schizosaccharomyces pombe Proteins / genetics
  • Schizosaccharomyces pombe Proteins / metabolism*
  • Temperature
  • Transcription, Genetic

Substances

  • Schizosaccharomyces pombe Proteins
  • Cyclin-Dependent Kinases
  • Cyclin-Dependent Kinase-Activating Kinase