Hexim1 sequesters positive transcription elongation factor b from the class II transactivator on MHC class II promoters.

ABSTRACT: The class II transactivator (CIITA) is the master integrator of expression of MHC class II genes. It interacts with variety of basal transcription factors to initiate and elongate transcription of these genes. Among others, it recruits positive transcription elongation factor b (P-TEFb) to MHC class II promoters. In cells, P-TEFb is found in small active or large inactive complexes. The large complex is composed of P-TEFb, 7SK small nuclear RNA, and hexamethylene bisacetamide-inducible protein 1 (Hexim1). The present study identifies Hexim1 as a potent inhibitor of CIITA-mediated transcription. Not only the exogenously expressed but also IFN-gamma-induced CIITA was inhibited by Hexim1. This inhibition did not result from an association between Hexim1 and CIITA but depended on the intact Cy

SUBMITTER: Kohoutek J 

PROVIDER: S-EPMC1859933 | biostudies-literature | 2006 Nov

REPOSITORIES: biostudies-literature