GATA-4, GATA-5, and GATA-6 activate the rat liver fatty acid binding protein gene in concert with HNF-1alpha.
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)-1alpha, and the proximal Fabpl GATA site adjoins an HNF-1 site. GATA-4, GATA-5, or GATA-6 bounded to HNF-1alpha in solution, and all cooperated with HNF-1alpha 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-1alpha. These in vitro results suggested GATA/HNF-1alpha 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-1alpha physical and functional interaction in Fabpl activation.
Divine
Joyce K
JK
Division of Biology and Biomedical Sciences, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Staloch
Lora J
LJ
Haveri
Hanna
H
Jacobsen
Christina M
CM
Wilson
David B
DB
Heikinheimo
Markku
M
Simon
Theodore C
TC
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000502:physiology*; D050556:Fatty Acid-Binding Proteins; D050991:GATA4 Transcription Factor; D050992:GATA5 Transcription Factor; D050993:GATA6 Transcription Factor; D041981:Gastrointestinal Tract / Q000166:cytology / Q000378:metabolism; D005786:Gene Expression Regulation / Q000502:physiology; D051537:Hepatocyte Nuclear Factor 1; D051538:Hepatocyte Nuclear Factor 1-alpha; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000502:physiology*; D011401:Promoter Regions, Genetic; D051381:Rats; D013539:Simian virus 40 / Q000235:genetics; D014018:Tissue Distribution; D014157:Transcription Factors / Q000502:physiology*; D019076:Transgenes
D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D050556:Fatty Acid-Binding Proteins; D050991:GATA4 Transcription Factor; D050992:GATA5 Transcription Factor; C494755:GATA5 protein, human; D050993:GATA6 Transcription Factor; C494759:GATA6 protein, human; C494756:Gata5 protein, mouse; C494757:Gata5 protein, rat; C494760:Gata6 protein, mouse; C496487:HNF1A protein, human; D051538:Hepatocyte Nuclear Factor 1-alpha; C496488:Hnf1a protein, mouse; C496489:Hnf1a protein, rat; D009687:Nuclear Proteins; D014157:Transcription Factors; D051537:Hepatocyte Nuclear Factor 1