Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P23193 (transcription elongation factor)
 739 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The 7SK small nuclear RNA (snRNA) regulates RNA polymerase II transcription elongation by controlling the protein kinase activity of the positive transcription elongation factor b (P-TEFb). In cooperation with HEXIM1, the 7SK snRNA sequesters P-TEFb into the kinase-inactive 7SK/HEXIM1/P-TEFb small nuclear ribonucleoprotein (snRNP), and thereby, controls the nuclear level of active P-TEFb. Here, we report that a fraction of HeLa 7SK snRNA that is not involved in 7SK/HEXIM1/P-TEFb formation, specifically interacts with RNA helicase A (RHA), heterogeneous nuclear ribonucleoprotein A1 (hnRNP), A2/B1, R and Q proteins. Inhibition of cellular transcription induces disassembly of 7SK/HEXIM1/P-TEFb and at the same time, increases the level of 7SK snRNPs containing RHA, hnRNP A1, A2/B1, R and Q. Removal of transcription inhibitors restores the original levels of the 7SK/HEXIM1/P-TEFb and '7SK/hnRNP' complexes. 7SK/HEXIM1/P-TEFb snRNPs containing mutant 7SK RNAs lacking the capacity for binding hnRNP A1, A2, R and Q are resistant to stress-induced disassembly, indicating that recruitment of the novel 7SK snRNP proteins is essential for disruption of 7SK/HEXIM1/P-TEFb. Thus, we propose that the nuclear level of active P-TEFb is controlled by dynamic and reversible remodelling of 7SK snRNP.
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PMID:Dynamic remodelling of human 7SK snRNP controls the nuclear level of active P-TEFb. 1761 2