Complex regulation of the lactase-phlorizin hydrolase promoter by GATA-4.
Lactase-phlorizin hydrolase (LPH), a marker of intestinal differentiation, is expressed in absorptive enterocytes on small intestinal villi in a tightly regulated pattern along the proximal-distal axis. The LPH promoter contains binding sites that mediate activation by members of the GATA-4, -5, and -6 subfamily, but little is known about their individual contribution to LPH regulation in vivo. Here, we show that GATA-4 is the principal GATA factor from adult mouse intestinal epithelial cells that binds to the mouse LPH promoter, and its expression is highly correlated with that of LPH mRNA in jejunum and ileum. GATA-4 cooperates with hepatocyte nuclear factor (HNF)-1alpha to synergistically activate the LPH promoter by a mechanism identical to that previously characterized for GATA-5/HNF-1alpha, requiring physical association between GATA-4 and HNF-1alpha and intact HNF-1 binding sites on the LPH promoter. GATA-4 also activates the LPH promoter independently of HNF-1alpha, in contrast to GATA-5, which is unable to activate the LPH promoter in the absence of HNF-1alpha. GATA-4-specific activation requires intact GATA binding sites on the LPH promoter and was mapped by domain-swapping experiments to the zinc finger and basic regions. However, the difference in the capacity between GATA-4 and GATA-5 to activate the LPH promoter was not due to a difference in affinity for binding to GATA binding sites on the LPH promoter. These data indicate that GATA-4 is a key regulator of LPH gene expression that may function through an evolutionarily conserved mechanism involving cooperativity with an HNF-1alpha and/or a GATA-specific pathway independent of HNF-1alpha.
van Wering
Herbert M
HM
Department of Medicine, Free University of Amsterdam, Amsterdam 1081HV.
Bosse
Tjalling
T
Musters
Anna
A
de Jong
Evelien
E
de Jong
Naomi
N
Hogen Esch
Caroline E
CE
Boudreau
Francois
F
Swain
Gary P
GP
Dowling
Lauren N
LN
Montgomery
Robert K
RK
Grand
Richard J
RJ
Krasinski
Stephen D
SD
D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation / Q000502:physiology; D004268:DNA-Binding Proteins / Q000378:metabolism*; D050991:GATA4 Transcription Factor; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D017930:Genes, Reporter; D051537:Hepatocyte Nuclear Factor 1; D051538:Hepatocyte Nuclear Factor 1-alpha; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology / Q000502:physiology*; D010694:Lactase-Phlorizin Hydrolase / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics*; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection; D016335:Zinc Fingers / Q000502:physiology
D004268:DNA-Binding Proteins; D050991:GATA4 Transcription Factor; C496487:HNF1A protein, human; D051538:Hepatocyte Nuclear Factor 1-alpha; C496488:Hnf1a protein, mouse; D009687:Nuclear Proteins; D014157:Transcription Factors; D051537:Hepatocyte Nuclear Factor 1; D010694:Lactase-Phlorizin Hydrolase