Cellular control of gene expression by T-type cyclin/CDK9 complexes.
The family of Cyclin-Dependent Kinases (CDKs) can be subdivided into two major functional groups based on their roles in cell cycle and/or transcriptional control. This review is centered on CDK9, which is activated by T-type cyclins and cyclin K generating distinct Positive-Transcription Elongation Factors termed P-TEFb. P-TEFb positively regulates transcriptional elongation by phosphorylating the C-terminal domain (CTD) of RNA polymerase II (RNA pol II), as well as negative elongation factors, which block elongation by RNA pol II shortly after the initiation of transcription. Work over the past few years has led to a dramatic increase in our understanding of how productive transcriptional elongation occurs. This review will briefly describe the mechanisms regulating the activity of T-type cyclin/CDK9 complexes and discuss how these complexes regulate gene expression. For further information, the reader is directed to excellent existing reviews on transcriptional elongation and HIV transcription.
Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, 3307 North Broad St., Philadelphia, PA 19140, USA.
Judit
J
Garriga
Xavier
X
Graña
D000818:Animals; D056906:Cyclin T; D042863:Cyclin-Dependent Kinase 9 / Q000235:genetics / Q000378:metabolism*; D016213:Cyclins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D008957:Models, Genetic; D042925:Positive Transcriptional Elongation Factor B / Q000378:metabolism; D011485:Protein Binding; D012319:RNA Polymerase II / Q000378:metabolism; D012342:RNA, Small Nuclear / Q000378:metabolism; D014158:Transcription, Genetic
C503684:CCNT1 protein, human; D056906:Cyclin T; D016213:Cyclins; D012342:RNA, Small Nuclear; D042925:Positive Transcriptional Elongation Factor B; D042863:Cyclin-Dependent Kinase 9; D012319:RNA Polymerase II