Transcription-dependent association of multiple positive transcription elongation factor units to a HEXIM multimer.

Details

Serval ID
serval:BIB_42521BA44F56
Type
Article: article from journal or magazin.
Collection
Publications
Title
Transcription-dependent association of multiple positive transcription elongation factor units to a HEXIM multimer.
Journal
Journal of Biological Chemistry
Author(s)
Dulac C., Michels A.A., Fraldi A., Bonnet F., Nguyen V.T., Napolitano G., Lania L., Bensaude O.
ISSN
0021-9258
Publication state
Published
Issued date
2005
Peer-reviewed
Oui
Volume
280
Number
34
Pages
30619-30629
Language
english
Notes
Publication types: Journal Article
Abstract
The positive transcription elongation factor (P-TEFb) comprises a kinase, CDK9, and a Cyclin T1 or T2. Its activity is inhibited by association with the HEXIM1 or HEXIM2 protein bound to 7SK small nuclear RNA. HEXIM1 and HEXIM2 were found to form stable homo- and hetero-oligomers. Using yeast two-hybrid and transfection assays, we have now shown that the C-terminal domains of HEXIM proteins directly interact with each other. Hydrodynamic parameters measured by glycerol gradient ultracentrifugation and gel-permeation chromatography demonstrate that both purified recombinant and cellular HEXIM1 proteins form highly anisotropic particles. Chemical cross-links suggest that HEXIM1 proteins form dimers. The multimeric nature of HEXIM1 is maintained in P-TEFb.HEXIM1.7SK RNA complexes. Multiple P-TEFb modules are found in the inactive P-TEFb.HEXIM1.7SK complexes. It is proposed that 7SK RNA binding to a HEXIM1 multimer promotes the simultaneous recruitment and hence inactivation of multiple P-TEFb units.
Keywords
Anisotropy, Centrifugation, Density Gradient, Cross-Linking Reagents/pharmacology, Cyclins/chemistry, Dimerization, Glycerol/pharmacology, Hela Cells, Humans, Immunoprecipitation, Plasmids/metabolism, Positive Transcriptional Elongation Factor B/chemistry, Positive Transcriptional Elongation Factor B/metabolism, Protein Binding, Protein Structure, Tertiary, RNA/chemistry, RNA-Binding Proteins/chemistry, RNA-Binding Proteins/metabolism, Recombinant Proteins/chemistry, Ribonucleoproteins, Small Nuclear/chemistry, Transcription, Genetic, Two-Hybrid System Techniques, Ultracentrifugation
Pubmed
Web of science
Open Access
Yes
Create date
28/07/2008 16:55
Last modification date
08/05/2019 17:43
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