Cyclin T2 is a member of the cyclin family of regulatory proteins that associate with and activate cyclin-dependent kinases (CDKs) to regulate cell cycle progression and transcription. The hallmark characteristic of cyclins is the periodicity of their expression and activity that is regulated transcriptionally and post-transcriptionally via phosphorylation and ubiquitination. Cyclin T2 is part of a group of cyclins that are involved in transcriptional regulation at the level of RNA transcription, initiation, elongation, and RNA processing. The transcriptional regulating cyclins include cyclin C, H, K, L1, L2, T1, and T2 which associate with CDK7, -8, -9, -10 and -12. Cyclin T2 associates with CDK9 and is a subunit of the transcription elongation factor p-TEFb. pTEFb is responsible for phosphorylating the carboxyl-terminal domain (CTD) of RNA polymerase II to facilitate elongation.