title: GATA-6 promotes cell survival by up-regulating BMP-2 expression during embryonic stem cell differentiation.
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.
authors.affiliation: Department of Surgery, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Brunswick, NJ 08903, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Rong
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Qi
authors.forename: Alan M
authors.initials: AM
authors.lastname: Graham
authors.forename: Michael S
authors.initials: MS
authors.lastname: Parmacek
authors.forename: Shaohua
authors.initials: S
authors.lastname: Li
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D055396:Bone Morphogenetic Protein 2 / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D002454:Cell Differentiation; D002460:Cell Line; D002470:Cell Survival; D058732:Embryoid Bodies / Q000166:cytology / Q000378:metabolism; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D004707:Endoderm / Q000378:metabolism / Q000648:ultrastructure; D050993:GATA6 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D005855:Germ Layers / Q000378:metabolism; D015151:Immunoblotting; D051379:Mice; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D009154:Mutation; D010766:Phosphorylation; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051785:Smad Proteins / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D015854:Up-Regulation
chemical_list: C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D050993:GATA6 Transcription Factor; D051785:Smad Proteins