Anti-CyclinT1

Cyclins function as regulators of CDK kinases and exhibit distinct expression and degradation patterns which contribute to the temporal coordination of each mitotic event. The cyclin-T1 protein (CCNT1) belongs to the highly conserved cyclin family, whose members are characterized by a dramatic periodicity in protein abundance through the cell cycle. CCNT1 tightly associates with CDK9 kinase, and was found to be a major subunit of the transcription elongation factor p-TEFb. The kinase complex containing CCNT1 and the elongation factor can interact with, and act as a cofactor of human immunodeficiency virus type 1 (HIV-1) Tat protein, and was shown to be both necessary and sufficient for full activation of viral transcription. CCNT1 and its kinase partner were also found to be involved in the phosphorylation and regulation of the carboxy-terminal domain (CTD) of the largest RNA polymerase II subunit.