GATA-4 is a novel transcription factor expressed in endocardium of the developing heart.
We have isolated and characterized Xenopus cDNA clones for a new transcription factor that represents an early marker for the developing heart. The cDNAs encode a protein that we have designated GATA-4; it contains the highly conserved DNA-binding domain that characterizes this family of cell-type restricted transcriptional activators. Whole-embryo in situ analysis of Xenopus embryos demonstrates that the GATA-4 gene is transcribed in presumptive cardiac ventral mesoderm at the time that bilateral progenitors fuse and form the cardiac tube. GATA-4 is therefore the earliest molecular marker of cardiogenesis yet characterized. By stage 30, the GATA-4 mRNA is expressed in the developing atria and ventricles; at stage 38, cross-sections reveal that the gene is active in the endocardial layer, but not in myocardium. By stage 40, GATA-4 message is detected in the great vessels. In the adult frog, the GATA-4 gene is highly transcribed in heart and gut; lower levels of message are detected in various endoderm-derived tissues and gonads. Expression in the stomach is largely confined to the epithelium. The GATA-4 gene is first activated at stage 11; mRNA is initially present throughout the marginal zone of explants and later partially localized to the ventral marginal zone. GATA-4 mRNA is also detected at high levels in cultured endodermal explants derived from the vegetal region of early embryos. In mesoderm induction experiments, GATA-4 transcription is not induced in animal caps treated with activin or bFGF. The GATA-4 gene may provide a new early marker for studying the inductive processes that lead to the formation of the cardiovascular system and for the specification of the endocardial lineage.
Kelley
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Children's Hospital, Harvard Medical School, Boston, MA 02115.
Blumberg
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Evans
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D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015415:Biomarkers; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D004699:Endocardium / Q000378:metabolism*; D050991:GATA4 Transcription Factor; D015870:Gene Expression; D006321:Heart / Q000196:embryology* / Q000254:growth & development; D008969:Molecular Sequence Data; D005810:Multigene Family; D009132:Muscles / Q000378:metabolism; D009928:Organ Specificity; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012867:Skin / Q000378:metabolism; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic; D014781:Viscera / Q000378:metabolism; D014981:Xenopus / Q000196:embryology / Q000235:genetics* / Q000254:growth & development; D029867:Xenopus Proteins
D015415:Biomarkers; D004268:DNA-Binding Proteins; D050991:GATA4 Transcription Factor; C494751:GATA4 protein, Xenopus; D014157:Transcription Factors; D029867:Xenopus Proteins