Smad2 and Smad3 differentially modulate chordin transcription via direct binding on the distal elements in gastrula Xenopus embryos

摘要: Abstract Transforming growth factor (TGF)β/activin superfamily regulates diverse biological processes including germ layer specification and axis patterning in vertebrates. TGFβ/activin leads to phosphorylation of Smad2 Smad3, followed by regulation their target genes. Activin treatment also induces the essential organizer gene chordin (chrd). The involvement Smad2/3 chrd expression has been unclear as whether is direct or indirect any cis-acting response elements for are present proximal distal regions its promoter. In study, we isolated the −2250 bps portion promoter, showing that it contained binding sites at portion, separate from locations other genes, goosecoid cerberus. pattern transcription activation promoter (−2250 bps) was indistinguishable endogenous gastrula Xenopus embryos. Reporter assays site-directed mutagenesis analysis mapped two active activin/Smad (ARE1 ARE2) Smad3. For a differential induction, acted on both ARE1 ARE2, but Smad3 only ARE2. Collectively, results demonstrate region contains which differentially modulate