GATA-4, GATA-5, and GATA-6 activate the rat liver fatty acid binding protein gene in concert with HNF-1α

Abstract

Transcriptional regulation by GATA-4, GATA-5, and GATA-6 in intestine and liver was explored using a transgene constructed from the proximal promoter of the rat liver fatty acid binding protein gene ( Fabpl). An immunohistochemical survey detected GATA-4 and GATA-6 in enterocytes, GATA-6 in hepatocytes, and GATA-5 in neither cell type in adult animals. In cell transfection assays, GATA-4 or GATA-5 but not GATA-6 activated the Fabpl transgene solely through the most proximal of three GATA binding sites in the Fabpl promoter. However, all three factors activated transgenes constructed from each Fabpl site upstream of a minimal viral promoter. GATA factors interact with hepatic nuclear factor (HNF)-1α, and the proximal Fabpl GATA site adjoins an HNF-1 site. GATA-4, GATA-5, or GATA-6 bounded to HNF-1α in solution, and all cooperated with HNF-1α to activate the Fabpl transgene. Mutagenizing all Fabpl GATA sites abrogated transgene activation by GATA factors, but GATA-4 activated the mutagenized transgene in the presence of HNF-1α. These in vitro results suggested GATA/HNF-1α interactions function in Fabpl regulation, and in vivo relevance was determined with subsequent experiments. In mice, the Fabpl transgene was active in enterocytes and hepatocytes, a transgene with mutagenized HNF-1 site was silent, and a transgene with mutagenized GATA sites had identical expression as the native transgene. Mice mosaic for biallelic Gata4 inactivation lost intestinal but not hepatic Fabpl expression in Gata4-deficient cells but not wild-type cells. These results demonstrate GATA-4 is critical for intestinal gene expression in vivo and suggest a specific GATA-4/HNF-1α physical and functional interaction in Fabpl activation.

The miR-363-GATA6-Lgr5 pathway is critical for colorectal tumourigenesis

“…For example, the homeodomain protein CDX2, a critical regulator of intestinal homeostasis, plays an important role in intestinal cell proliferation by interacting with GATA6 at active chromatins 25 . Hepatocyte nuclear factor (HNF) family proteins also cooperate with GATA6 to regulate gene expression 36,37 . Furthermore, several HNF-binding motifs are present just proximal to the GATA6-binding site in the promoter region of Lgr5.…”

Hepatocyte nuclear factor-4α promotes differentiation of intestinal epithelial cells in a coculture system

“…A number of regulators crucial to sustain the transcriptional activity of intestinal specific gene promoters have been identified (6,7,11,49,58). Characterization of the expression profile of some of these transcriptional modulators during the progression of the cocultures was next undertaken.…”

“…HNF-1␣ was shown to participate in the transcriptional regulation of several intestinal specific genes (6,11,31,46,57,60). HNF-4␣ was recently suggested to act as a regulator of villus specific epithelial genes (53).…”

GATA‐4:FOG interactions regulate gastric epithelial development in the mouse

“…Embryos or tissues were fixed in 4% paraformaldehyde, embedded in paraffin, sectioned (4 m), and then processed for immunohistochemistry as previously described (Narita et al, 1997a;Ketola et al, 1999;Bielinska et al, 2003;Divine et al, 2004). Sections were stained with the following antibodies: (1) goat anti-GATA-4 (dilution 1:200, sc-1237 Santa Cruz Biotechnology, Santa Cruz, CA); (2) goat anti-FOG-1 (dilution 1:1,000, sc-9361 Santa Cruz Biotechnology); and (3) goat anti-FOG-2 (dilution 1:1,000, sc-9365 Santa Cruz Biotechnology).…”