Nodal and Smad2/3 signals play pivotal roles in mesendoderm induction and axis determination during late blastulation and early gastrulation in vertebrate embryos. However, Smad2/3 direct target genes during those critical developmental stages have not been systematically identified. Here, through ChIP-chip assay, we show that the promoter/enhancer regions of 679 genes are bound by Smad2 in the zebrafish early gastrulas. Expression analyses confirm that a significant proportion of Smad2 targets are indeed subjected to Nodal/Smad2 regulation at the onset of gastrulation. The co-existence of DNA-binding sites of other transcription factors in the Smad2-bound regions allows the identification of well known Smad2-binding partners, such as FoxH1 and Lef1/β-catenin, as well as many previously unknown Smad2 partners, including Oct1 and Gata6, during embryogenesis. We demonstrate that Oct1 physically associates with and enhances the transcription and mesendodermal induction activity of Smad2, whereas Gata6 exerts an inhibitory role in Smad2 signaling and mesendodermal induction. Thus, our study systemically uncovers a large number of Smad2 targets in early gastrulas and suggests cooperative roles of Smad2 and other transcription factors in controlling target gene transcription, which will be valuable for studying regulatory cascades during germ layer formation and patterning of vertebrate embryos.
Pubmed ID: 21669877 RIS Download
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Database which provides on-line searching of microarray datasets generated from rat spinal cord after contusion injury. Both the primary injury site and a site 5 mm distal to the injury site were assayed. Tissue was obtained from Long Evans rats subject to spinal cord contusion injury using the MASCIS impactor (formerly known as the NYU impactor). RNA expression was assayed at the site of injury and distal to the site of injury using the Affymetrix Rat Neuro U34 chip.
View all literature mentionsCell line HEK293T is a Transformed cell line with a species of origin Homo sapiens (Human)
View all literature mentionsCell line HEK293 is a Transformed cell line with a species of origin Homo sapiens (Human)
View all literature mentionsCell line HaCaT is a Spontaneously immortalized cell line with a species of origin Homo sapiens (Human)
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