Drosophila Cdk8, a kinase partner of cyclin C that interacts with the large subunit of RNA polymerase II.
A number of cyclins have been described, most of which act together with their catalytic partners, the cyclin-dependent kinases (Cdks), to regulate events in the eukaryotic cell cycle. Cyclin C was originally identified by a genetic screen for human and Drosophila cDNAs that complement a triple knock-out of the CLN genes in Saccharomyces cerevisiae. Unlike other cyclins identified in this complementation screen, there has been no evidence that cyclin C has a cell-cycle role in the cognate organism. Here we report that cyclin C is a nuclear protein present in a multiprotein complex. It interacts both in vitro and in vivo with Cdk8, a novel protein-kinase of the Cdk family, structurally related to the yeast Srb10 kinase. We also show that Cdk8 can interact in vivo with the large subunit of RNA polymerase II and that a kinase activity that phosphorylates the RNA polymerase II large subunit is present in Cdk8 immunoprecipitates. Based on these observations and sequence similarity to the kinase/cyclin pair Srb10/Srb11 in S. cerevisiae, we suggest that cyclin C and Cdk8 control RNA polymerase II function.
Leclerc
V
V
URA 671 Centre National de la Recherche Scientifique, Villefranche-sur-mer, France.
Tassan
J P
JP
O'Farrell
P H
PH
Nigg
E A
EA
Léopold
P
P
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002846:Chromatography, Affinity; D003001:Cloning, Molecular; D056745:Cyclin C; D056850:Cyclin-Dependent Kinase 8; D018844:Cyclin-Dependent Kinases; D016213:Cyclins / Q000378:metabolism*; D004330:Drosophila; D029721:Drosophila Proteins; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011487:Protein Conformation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D012319:RNA Polymerase II / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins
C503674:CCNC protein, human; C503678:CycC protein, Drosophila; D056745:Cyclin C; D016213:Cyclins; D029721:Drosophila Proteins; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D005982:Glutathione Transferase; D017346:Protein Serine-Threonine Kinases; C095686:CDK8 protein, human; C498308:Cdk8 protein, Drosophila; D056850:Cyclin-Dependent Kinase 8; D018844:Cyclin-Dependent Kinases; C498309:SSN3 protein, S cerevisiae; D012319:RNA Polymerase II