Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P51532 (transcriptional activator)
 6,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In Xenopus, the Spemann-Mangold organizer induces and patterns the body axis. Siamois, a Wnt-responsive transcriptional activator, functions to establish and maintain the Spemann-Mangold organizer by regulating organizer gene transcription. While expression of Siamois in marginal blastomeres induces an axis consisting of both head and trunk structures, we show that expression of Siamois in animal blastomeres induces an axis that lacks head structures. Consistent with the absence of head organizer activity in Siamois-expressing animal pole tissue, Siamois did not induce animal expression of Cerberus, Frzb1 and Xlim1, genes implicated in anterior development. A dominant negative form of Siamois inhibited endogenous expression of Cerberus, Frzb1 and Xlim1, indicating that Siamois is necessary for organizer-specific expression of these head organizer genes, but is not sufficient in animal tissue. Siamois induces Cerberus, Frzb1 and Xlim1 in vegetal blastomeres and vegetal induction by Siamois is dependent on endogenous TGFbeta signals. The results provide evidence that Siamois cooperates with TGFbeta signals to activate the expression of organizer genes and to generate an organizer with both head- and trunk-inducing activity.
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PMID:Siamois cooperates with TGFbeta signals to induce the complete function of the Spemann-Mangold organizer. 1129 53

Early in vertebrate development, endodermal signals act on mesoderm to induce cardiogenesis. The F-type SOXs SOX7 and SOX18beta are expressed in the cardiogenic region of the early Xenopus embryo. Injection of RNAs encoding SOX7 or SOX18beta, but not the related F-type SOX, SOX17, leads to the nodal-dependent expression of markers of cardiogenesis in animal cap explants. Injection of morpholinos directed against either SOX7 or SOX18mRNAs lead to a partial inhibition of cardiogenesis in vivo, while co-injection of SOX7 and SOX18 morpholinos strongly inhibited cardiogenesis. SOX7 RNA rescued the effects of the SOX18 morpholino and visa versa, indicating that the proteins have redundant functions. In animal cap explants, it appears that SOX7 and SOX18 act indirectly through Xnr2 to induce mesodermal (Eomesodermin, Snail, Wnt11), organizer (Cerberus) and endodermal (endodermin, Hex) tissues, which then interact to initiate cardiogenesis. Versions of SOX7 and SOX18 with their C-terminal, beta-catenin interaction domains replaced by a transcriptional activator domain failed to antagonize beta-catenin activation of Siamois, but still induced cardiogenesis. These observations identify SOX7 and SOX18 as important, and previously unsuspected, regulators of cardiogenesis in Xenopus.
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PMID:SOX7 and SOX18 are essential for cardiogenesis in Xenopus. 1619 13