XXXX -hypersensitive sites enhance alpha1(I) collagen gene expression in hepatic stellate cells.

@entity82 @entity14605 @entity19 @entity1575 @entity9828 @entity9829
@entity1575 is characterized by a dramatic increase in the expression of type I collagen. Several deoxyribonuclease (DNase) I-hypersensitive sites (HS) have been located in the distal 5'-flanking region of the alpha1(I) collagen gene that are specific to collagen-producing cells. To assess the role of the @entity9828 -HS in regulating alpha1(I) collagen gene expression in hepatic stellate cells (HSCs), 3 transgenic @entity19 lines expressing collagen-alpha1(I) reporter genes were used (Krempen et al. Gene Expr 1999;8:151-163). The pCol9GFP transgene contains the collagen gene promoter (-3122 to +111) linked to the green fluorescent protein (GFP) reporter gene. The pCol9GFP-HS4,5 transgene contains HS4,5 and pColGFP-HS8,9 contains HS8,9 positioned upstream of the collagen promoter in pCol9GFP. HSCs isolated from @entity19 containing pCol9GFPHS4,5 and pColGFP-HS8,9 showed earlier and higher GFP expression patterns than HSCs isolated from pCol9GFP @entity19 . HSCs from pCol9GFP-HS4,5 showed the highest levels of GFP expression and culture-induced expression correlated with induction of the endogenous alpha1(I) collagen gene. After @entity14605 administration, pCol9GFP-HS4,5 @entity19 showed increased GFP expression compared with pCol9GFP @entity19 in both whole liver extracts and isolated HSCs. Several sites for DNA-protein interactions in both HS4 and HS5 were identified that included a binding site for @entity9829 . In conclusion, @entity9828 -HS4,5 enhance expression of the alpha1(I) collagen gene promoter in HSCs both in vitro and in vivo after a fibrogenic stimulus. The collagen-GFP @entity19 provide a convenient and reliable model system to investigate the molecular mechanisms controlling increased collagen expression during @entity82 .
