IN VITRO ASSEMBLY OF A FUNCTIONAL HUMAN CDK7-CYCLIN H COMPLEX REQUIRES MAT1, A NOVEL 36 KDA RING FINGER PROTEIN

摘要: It is proposed that the CDK7-cyclin H complex functions in cell cycle progression, basal transcription and DNA repair. Here we report vitro reconstitution of an active requires stoichiometric amounts a novel 36 kDa assembly factor termed MAT1 (menage trois 1). Sequencing reveals putative zinc binding motif (a C3HC4 RING finger) N-terminus; however, this domain not required for ternary formation with H. associated nuclear at all stages vivo. Ternary complexes CDK7, cyclin display kinase activity towards substrates mimicking both T-loop CDKs C-terminal RNA polymerase II, regardless whether they are immunoprecipitated from HeLa cells or reconstituted reticulocyte lysate. constitutes first example appears to be essential CDK-cyclin complex.