DNA-binding specificity and embryological function of Xom (Xvent-2).
Xom (also known as Xvent-2) is a homeobox-containing gene expressed throughout the early gastrula of the Xenopus embryo with the exception of the organizer. Activation of Xom is an immediate-early response to BMP signaling, and overexpression of Xom, like overexpression of BMP family members, causes ventralization of the embryo. In this paper we first show that Xom is a transcriptional repressor and we then define its preferred DNA-binding site. Overexpression of wild-type Xom and a dominant-negative form suggests that Xom functions by repressing transcription of goosecoid, and analysis of the goosecoid promoter reveals a site which is required for Xom-mediated repression of goosecoid promoter reporter constructs. Together, these results suggest that Xom causes down-regulation of goosecoid in a direct fashion and that this accounts, at least in part, for the ability of Xom to cause ventralization of the Xenopus embryo.
Trindade
M
M
Division of Developmental Biology, National Institute for Medical Research, London, United Kingdom.
Tada
M
M
Smith
J C
JC
D028341:Activins; D000818:Animals; D001665:Binding Sites; D019521:Body Patterning; D019556:COS Cells; D016384:Consensus Sequence; D004268:DNA-Binding Proteins / Q000032:analysis / Q000378:metabolism; D015536:Down-Regulation; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D051956:Goosecoid Protein; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D017403:In Situ Hybridization; D007265:Inhibins / Q000378:metabolism; D017354:Point Mutation; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000235:genetics; D014157:Transcription Factors; D014162:Transfection; D014981:Xenopus / Q000196:embryology*; D029867:Xenopus Proteins
D004268:DNA-Binding Proteins; D051956:Goosecoid Protein; D018398:Homeodomain Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D029867:Xenopus Proteins; C099992:ventx2.1 protein, Xenopus; D028341:Activins; D007265:Inhibins