GATA4 and GATA6 control mouse pancreas organogenesis
Manuel Carrasco, … , Francisco Martín, Anabel Rojas
Manuel Carrasco, … , Francisco Martín, Anabel Rojas
Published September 24, 2012
Citation Information: J Clin Invest. 2012;122(10):3504-3515. https://doi.org/10.1172/JCI63240.
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GATA4 and GATA6 control mouse pancreas organogenesis

Abstract

Recently, heterozygous mutations in GATA6 have been found in neonatal diabetic patients with failed pancreatic organogenesis. To investigate the roles of GATA4 and GATA6 in mouse pancreas organogenesis, we conditionally inactivated these genes within the pancreas. Single inactivation of either gene did not have a major impact on pancreas formation, indicating functional redundancy. However, double Gata4/Gata6 mutant mice failed to develop pancreata, died shortly after birth, and displayed hyperglycemia. Morphological defects in Gata4/Gata6 mutant pancreata were apparent during embryonic development, and the epithelium failed to expand as a result of defects in cell proliferation and differentiation. The number of multipotent pancreatic progenitors, including PDX1+ cells, was reduced in the Gata4/Gata6 mutant pancreatic epithelium. Remarkably, deletion of only 1 Gata6 allele on a Gata4 conditional knockout background severely reduced pancreatic mass. In contrast, a single WT allele of Gata4 in Gata6 conditional knockout mice was sufficient for normal pancreatic development, indicating differential contributions of GATA factors to pancreas formation. Our results place GATA factors at the top of the transcriptional network hierarchy controlling pancreas organogenesis.

Authors

Manuel Carrasco, Irene Delgado, Bernat Soria, Francisco Martín, Anabel Rojas

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Figure 6

GATA4 and GATA6 bind to the Pdx1 conserved area III in vitro and in pancreatic cell line.

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GATA4 and GATA6 bind to the Pdx1 conserved area III in vitro and in panc...
(A) Highly conserved region in the cis-regulatory area III of Pdx1. Two conserved GATA sites, as revealed by bioinformatics analysis, are shown in blue boxes. Numbers indicate the position of the GATA sites relative to the Pdx1 translational start site. Point mutations introduced into GATA sites, G1m and G2m, are indicated in red lowercase. Asterisks denote nucleotides that have been perfectly conserved between mouse and human. (B) Recombinant GATA4 and GATA6 proteins are able to bind to G1 and G2 GATA sites of the Pdx1 enhancer as shown by EMSA. Competition experiments were performed by adding excess unlabeled probes of G1, G2, or control (denoted as c in competitor row) GATA sites, and the corresponding mutant versions (G1m, G2m, or cm) to the binding reaction. (C) ChIP experiments performed in mouse pancreatic ductal cells (mPAC cells) using specific GATA4 and GATA6 antibodies (lanes 2, 3, respectively) and nonspecific anti-IgG (lane 4) show that anti-GATA4 and anti-GATA6 antibodies are able to immunoprecipitate the GATA sites of the Pdx1 conserved area III, but not nonspecific genomic regions. Lane 1 contains PCR products from input DNA (Inp) amplified prior to immunoprecipitation. Sizes of the PCR products in bp are shown on the right. (D) A WT Pdx1 promoter-luciferase construct (pGL3-Pdx1-WT) is significantly activated by endogenous factors present in mPAC cells compared with the activity of the empty reporter pGL3 vector. Mutations in the GATA sites of Pdx1 (pGL3-Pdx1-mut) significantly attenuate the luciferase activity. *P = 0.002; **P = 0.005.