GATA-6 promotes cell survival by up-regulating BMP-2 expression during embryonic stem cell differentiation

Mol Biol Cell. 2012 Sep;23(18):3754-63. doi: 10.1091/mbc.E12-04-0313. Epub 2012 Aug 1.

Abstract

GATA-6 is a zinc-finger transcription factor essential for early embryogenesis. Ablation of GATA-6 in mice impairs endoderm differentiation and causes apoptosis of epiblast cells. The endoderm defects have been attributed to the loss of HNF4, disabled-2, and GATA-4. However, the mechanisms underlying epiblast apoptosis are unclear. In this study we used mouse embryonic stem cell-derived embryoid bodies (EBs) as a model for peri-implantation development and found that ablation of GATA-6 causes massive apoptosis during EB differentiation. Endoderm grafting experiments and ectopic basement membrane (BM) assembly suggest that both BM and non-BM factors contribute to cell survival. Furthermore, the increased cell death in mutant EBs is accompanied by reduced expression of bone morphogenetic protein 2 (BMP-2). Chromatin immunoprecipitation reveals direct binding of GATA-6 to the Bmp2 promoter. Treatment of the mutant EBs with BMP-2 markedly suppresses apoptosis, whereas stable overexpression of the BMP antagonist noggin or a dominant-negative BMP receptor in normal EBs leads to increased apoptosis. Last, activation of SMAD1/5 by phosphorylation is significantly inhibited in the absence of GATA-6, and this is reversed by exogenous BMP-2. Treatment of normal EBs with SMAD phosphorylation inhibitor increases apoptosis. Collectively these results suggest that GATA-6 promotes cell survival by regulating endoderm expression of BMP-2 and BM during embryonic epithelial morphogenesis.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Apoptosis / genetics
  • Bone Morphogenetic Protein 2 / genetics
  • Bone Morphogenetic Protein 2 / metabolism*
  • Bone Morphogenetic Protein 2 / pharmacology
  • Cell Differentiation*
  • Cell Line
  • Cell Survival
  • Embryoid Bodies / cytology
  • Embryoid Bodies / metabolism
  • Embryonic Stem Cells / cytology
  • Embryonic Stem Cells / metabolism*
  • Endoderm / metabolism
  • Endoderm / ultrastructure
  • GATA6 Transcription Factor / genetics
  • GATA6 Transcription Factor / metabolism*
  • Gene Expression Profiling
  • Germ Layers / metabolism
  • Immunoblotting
  • Mice
  • Microscopy, Electron
  • Microscopy, Fluorescence
  • Mutation
  • Phosphorylation
  • Promoter Regions, Genetic / genetics
  • Protein Binding
  • Reverse Transcriptase Polymerase Chain Reaction
  • Smad Proteins / genetics
  • Smad Proteins / metabolism
  • Time Factors
  • Up-Regulation

Substances

  • Bmp2 protein, mouse
  • Bone Morphogenetic Protein 2
  • GATA6 Transcription Factor
  • Smad Proteins