DNA-binding specificity and embryological function of Xom (Xvent-2)

Dev Biol. 1999 Dec 15;216(2):442-56. doi: 10.1006/dbio.1999.9507.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activins
  • Animals
  • Binding Sites
  • Body Patterning
  • COS Cells
  • Consensus Sequence
  • DNA-Binding Proteins / analysis
  • DNA-Binding Proteins / metabolism
  • Down-Regulation
  • Gene Expression Regulation, Developmental
  • Genes, Reporter
  • Goosecoid Protein
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism*
  • In Situ Hybridization
  • Inhibins / metabolism
  • Point Mutation
  • Promoter Regions, Genetic
  • Repressor Proteins / genetics
  • Transcription Factors*
  • Transfection
  • Xenopus / embryology*
  • Xenopus Proteins*

Substances

  • DNA-Binding Proteins
  • Goosecoid Protein
  • Homeodomain Proteins
  • Repressor Proteins
  • Transcription Factors
  • Xenopus Proteins
  • ventx2.1 protein, Xenopus
  • Activins
  • Inhibins