MAQ1 and 7SK RNA interact with CDK9/cyclin T complexes in a transcription-dependent manner.

Details

Serval ID
serval:BIB_5F83D8C4ABBF
Type
Article: article from journal or magazin.
Collection
Publications
Title
MAQ1 and 7SK RNA interact with CDK9/cyclin T complexes in a transcription-dependent manner.
Journal
Molecular and Cellular Biology
Author(s)
Michels A.A., Nguyen V.T., Fraldi A., Labas V., Edwards M., Bonnet F., Lania L., Bensaude O.
ISSN
0270-7306
Publication state
Published
Issued date
2003
Peer-reviewed
Oui
Volume
23
Number
14
Pages
4859-4869
Language
english
Abstract
Positive transcription elongation factor b (P-TEFb) comprises a cyclin (T1 or T2) and a kinase, cyclin-dependent kinase 9 (CDK9), which phosphorylates the carboxyl-terminal domain of RNA polymerase II. P-TEFb is essential for transcriptional elongation in human cells. A highly specific interaction among cyclin T1, the viral protein Tat, and the transactivation response (TAR) element RNA determines the productive transcription of the human immunodeficiency virus genome. In growing HeLa cells, half of P-TEFb is kinase inactive and binds to the 7SK small nuclear RNA. We now report on a novel protein termed MAQ1 (for ménage à quatre) that is also present in this complex. Since 7SK RNA is required for MAQ1 to associate with P-TEFb, a structural role for 7SK RNA is proposed. Inhibition of transcription results in the release of both MAQ1 and 7SK RNA from P-TEFb. Thus, MAQ1 cooperates with 7SK RNA to form a novel type of CDK inhibitor. According to yeast two-hybrid analysis and immunoprecipitations from extracts of transfected cells, MAQ1 binds directly to the N-terminal cyclin homology region of cyclins T1 and T2. Since Tat also binds to this cyclin T1 N-terminal domain and since the association between 7SK RNA/MAQ1 and P-TEFb competes with the binding of Tat to cyclin T1, we speculate that the TAR RNA/Tat lentivirus system has evolved to subvert the cellular 7SK RNA/MAQ1 system.
Keywords
Amino Acid Sequence, Base Sequence, Cell Nucleus/genetics, Cell Nucleus/metabolism, Cyclin-Dependent Kinase 9, Cyclin-Dependent Kinases/genetics, Cyclin-Dependent Kinases/metabolism, Cyclins/genetics, Cyclins/metabolism, Gene Products, tat/genetics, Gene Products, tat/metabolism, HIV Long Terminal Repeat/physiology, Hela Cells, Humans, Macromolecular Substances, Molecular Sequence Data, Positive Transcriptional Elongation Factor B, Protein Subunits/metabolism, Protein-Serine-Threonine Kinases/genetics, Protein-Serine-Threonine Kinases/metabolism, RNA, Small Nuclear/metabolism, RNA-Binding Proteins/genetics, RNA-Binding Proteins/metabolism, Sequence Homology, Amino Acid, Transcription, Genetic, Transfection, Two-Hybrid System Techniques
Pubmed
Web of science
Open Access
Yes
Create date
28/07/2008 16:03
Last modification date
20/08/2019 14:17
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