NFkappaB p50-CCAAT/enhancer-binding protein beta (C/EBPbeta)-mediated transcriptional repression of microRNA let-7i following microbial infection.

ABSTRACT: MicroRNAs, central players of numerous cellular processes, regulate mRNA stability or translational efficiency. Although these molecular events are established, the mechanisms regulating microRNA function and expression remain largely unknown. The microRNA let-7i regulates Toll-like receptor 4 expression. Here, we identify a novel transcriptional mechanism induced by the protozoan parasite Cryptosporidium parvum and Gram(-) bacteria-derived lipopolysaccharide (LPS) mediating let-7i promoter silencing in human biliary epithelial cells (cholangiocytes). Using cultured cholangiocytes, we show that microbial stimulus decreased let-7i expression, and promoter activity. Analysis of the mechanism revealed that microbial infection promotes the formation of a NFkappaB p50-C/EBPbeta silencer complex

SUBMITTER: O'Hara SP 

PROVIDER: S-EPMC2804168 | biostudies-literature | 2010 Jan

REPOSITORIES: biostudies-literature