Journal article
Identification of multiple cyclin subunits of human P-TEFb
Genes & development, Vol.12(5), pp.755-762
03/01/1998
DOI: 10.1101/gad.12.5.755
PMCID: PMC316581
PMID: 9499409
Abstract
The transition from abortive into productive elongation is proposed to be controlled by a positive transcription elongation factor b (P-TEFb) through phosphorylation of the carboxy-terminal domain (CTD) of the largest subunit of RNA polymerase II.
Drosophila
P-TEFb was identified recently as a cyclin-dependent kinase (CDK9) paired with a cyclin subunit (cyclin T). We demonstrate here the cloning of multiple cyclin subunits of human P-TEFb (T1 and T2). Cyclin T2 has two forms (T2a and T2b) because of alternative splicing. Both cyclin T1 and T2 are ubiquitously expressed. Immunoprecipitation and immunodepletion experiments carried out on HeLa nuclear extract (HNE) indicated that cyclin T1 and T2 were associated with CDK9 in a mutually exclusive manner and that almost all CDK9 was associated with either cyclin T1 or T2. Recombinant CDK9/cyclin T1, CDK9/cyclin T2a, and CDK9/cyclin T2b produced in Sf9 cells possessed DRB-sensitive kinase activity and functioned in transcription elongation in vitro. Either cyclin T1 or T2 was required to activate CDK9, and the truncation of the carboxyl terminus of the cyclin reduced, but did not eliminate, P-TEFb activity. Cotransfection experiments indicated that all three CDK9/cyclin combinations dramatically activated the CMV promoter.
Details
- Title: Subtitle
- Identification of multiple cyclin subunits of human P-TEFb
- Creators
- Junmin Peng - Department of Biochemistry, University of Iowa, Iowa City, Iowa 52242 USAYuerong Zhu - Department of Biochemistry, University of Iowa, Iowa City, Iowa 52242 USAJeffrey T Milton - Department of Biochemistry, University of Iowa, Iowa City, Iowa 52242 USADavid H Price - Department of Biochemistry, University of Iowa, Iowa City, Iowa 52242 USA
- Resource Type
- Journal article
- Publication Details
- Genes & development, Vol.12(5), pp.755-762
- Publisher
- Cold Spring Harbor Laboratory Press
- DOI
- 10.1101/gad.12.5.755
- PMID
- 9499409
- PMCID
- PMC316581
- ISSN
- 0890-9369
- eISSN
- 1549-5477
- Language
- English
- Date published
- 03/01/1998
- Academic Unit
- Biochemistry and Molecular Biology
- Record Identifier
- 9984025262302771
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