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

49Citations
Citations of this article
22Readers
Mendeley users who have this article in their library.

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·TSK RNA complexes. Multiple P-TEFb modules are found in the inactive P-TEFb·HEXIM1·7SK complexes. It is proposed that TSK RNA binding to a HEXIM1 multimer promotes the simultaneous recruitment and hence inactivation of multiple P-TEFb units. © 2005 by The American Society for Biochemistry and Molecular Biology, Inc.

Cite

CITATION STYLE

APA

Dulac, C., Michels, A. A., Fraldi, A., Bonnet, F., Nguyen, V. T., Napolitano, G., … Bensaude, O. (2005). Transcription-dependent association of multiple positive transcription elongation factor units to a HEXIM multimer. Journal of Biological Chemistry, 280(34), 30619–30629. https://doi.org/10.1074/jbc.M502471200

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free