Sign up for Table of Contents Alerts.

Email this page

Print this page

Review

HEXIM1 and the Control of Transcription Elongation: From Cancer and Inflammation to AIDS and Cardiac Hypertrophy

Anwesha Dey, Sheng-Hao Chao and David Lane

Purchase article for $19

Subscribe to this journal for $129/year

Hexamethylene bis-acetamide inducible protein 1 (HEXIM1) is an inhibitor of positive transcription elongation factor b (P-TEFb) that has recently been shown to be involved in cancers, AIDS, cardiac hypertrophy, and inflammation. It was first cloned from vascular smooth muscle cells (VSMCs) treated with hexamethylene bis-acetamide (HMBA), a compound that suppresses the proliferation of VSMCs. Little was known about the biological function of HEXIM1 till the discovery of its association with P-TEFb. P-TEFb, a protein complex composed of cyclin-dependent kinase 9 and a cyclin partner, plays a key role in regulation of RNA polymerase II elongation. When associated with 7SK small nuclear RNA, HEXIM1 binds to P-TEFb and inhibits the kinase activity of P-TEFb. This finding provides the molecular basis for the inhibitory function of HEXIM1 in P-TEFb-dependent transcription, such as human immunodeficiency virus Tat transactivation and NF-κB-mediated transcription. Recent evidences suggest an essential role of HEXIM1 in several diseases through transcriptional regulation.

Authors

Anwesha Dey

Institute of Molecular and Cell Biology; Proteos, Singapore

Sheng-Hao Chao

Bioprocessing Technology Institute; Centros, Singapore

David Lane

Prous Institute for Biomedical Research.com

Purchase article for $19

Subscribe to this journal for $129/year