CCNT2
Description
The CCNT2 (cyclin T2) is a protein-coding gene located on chromosome 2.
Cyclin-T2 is a protein that in humans is encoded by the CCNT2 gene. The protein encoded by this gene belongs to the highly conserved cyclin family, whose members are characterized by a dramatic periodicity in protein abundance through the cell cycle. Cyclins function as regulators of CDK kinases. Different cyclins exhibit distinct expression and degradation patterns which contribute to the temporal coordination of each mitotic event. This cyclin and its kinase partner CDK9 were found to be subunits of the transcription elongation factor p-TEFb. The p-TEFb complex containing this cyclin was reported to interact with, and act as a negative regulator of human immunodeficiency virus type 1 (HIV-1) Tat protein. Two alternatively spliced transcript variants, which encode distinct isoforms, have been described. Cyclin T2 has been shown to interact with CDK9 and Retinoblastoma protein.
Cyclin-T2 is a regulatory subunit of the cyclin-dependent kinase pair (CDK9/cyclin T) complex, also known as positive transcription elongation factor B (P-TEFB). P-TEFB facilitates the transition from abortive to production elongation by phosphorylating the CTD (carboxy-terminal domain) of the large subunit of RNA polymerase II (RNAP II). The activity of this complex is regulated by binding with 7SK snRNA. Cyclin-T2 plays a role during muscle differentiation, interacting with MYOD1. This tripartite complex promotes MYOD1's transcriptional activity through CDK9-mediated phosphorylation and binds the chromatin of promoters and enhancers of muscle-specific genes, correlating with hyperphosphorylation of the CTD domain of RNA pol II. Cyclin-T2 further enhances MYOD1-dependent transcription through interaction with PKN1. It is also involved in early embryo development.
CCNT2 is also known as CYCT2.
