Cyclins are eukaryotic proteins that play an active role in controlling nuclear cell division cycles [], and regulate cyclin dependent kinases (CDKs). This entry represents cyclin-T2. It is a regulatory subunit of the cyclin-dependent kinase pair (CDK9/cyclin T) complex, also called positive transcription elongation factor B (P-TEFB), which 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) []. Cyclin-T2 contains two domains that target RNAPII, and this substrate recognition is necessary for its transcriptional activity via DNA []. In mice, cyclin-T2 is essential for embryogenesis [].
