Disease relevance of goosecoid

• To investigate the mechanism of this inhibition, we ectopically expressed goosecoid in erythroleukemia cells [1].

High impact information on goosecoid

• In normal development, Siamois mRNA is first detected shortly after the midblastula transition, which is earlier than mRNAs for goosecoid or Xbrachyury, and is present most abundantly in the dorsal endoderm of early gastrulae [2].
• The expression of chordin starts in Spemann's organizer subsequent to that of goosecoid, and its induction by activin requires de novo protein synthesis [3].
• A Xenopus gene whose expression can be activated by the organizer-specific homeobox genes goosecoid and Xnot2 was isolated by differential screening [3].
• The homeobox gene goosecoid controls cell migration in Xenopus embryos [4].
• Goosecoid (gsc), a homeobox gene expressed specifically in the dorsal blastopore lip of the Xenopus gastrula, is considered to play an important role in Spemann's organizer phenomenon [4].

Biological context of goosecoid

• The possible functions of Wnt-like and activin-like signals and of the goosecoid homeobox gene, and their order of action in the formation of Spemann's organizer are discussed [5].
• Analysis of the embryonic phenotypes and goosecoid levels reveals that chimeras composed of carboxy-terminal regions of Xwnt-8 and amino-terminal regions of Xwnt-5A are indistinguishable from the activities of native Xwnt-8 and that are the reciprocal chimeras elicit effects indistinguishable from overexpression of native Xwnt-5A [6].
• We show that, in contrast to Spemann organiser genes such as goosecoid, chordin and noggin, Siamois gene expression is not induced following overexpression of mesoderm inducers in ectodermal (animal cap) cells [7].
• The XFD protein inhibits the expression of the immediate early gene brachyury throughout the marginal zone, including the dorsal side; it does not, however, inhibit the dorsal lip marker goosecoid, which is expressed in the first involuting mesoderm at the dorsal side that will underlie the head [8].
• Replacement of Xvent-2 target sites within the goosecoid (gsc) promoter by the BMP-4 enhancer converts Xvent-2 caused repression of gsc to strong activation [9].

Anatomical context of goosecoid

• Small changes (twofold) in the amount of microinjected messenger RNA encoding the goosecoid (gsc) homeodomain protein resulted in marked changes in the differentiation of mesoderm in Xenopus laevis [10].
• Xwnt-8 injection produces complete secondary axes including head structures whereas activin and goosecoid injection produce partial secondary axes at high frequency that lack head structures anterior to the auditory vesicle and often lack notochord [5].
• Endogenous gsc messenger RNA was expressed in the marginal zone in a graded fashion that is congruent with a role for this gene in dorso-ventral patterning of mesoderm at the early gastrula stage [10].
• Blastula-stage explants grafted onto activin-expressing oocytes expressed the mesodermal marker genes brachyury, goosecoid, and muscle actin [11].
• This phenotype is unlikely to result from Xwnt-5A acting as an inducing agent, as overexpression of Xwnt-5A does not rescue dorsal structures in UV-irradiated embryos, does not induce mesoderm in blastula caps, and Xwnt-5A does not alter the endogenous patterns of expression of goosecoid, Xbra, or Xwnt-8 [12].

Associations of goosecoid with chemical compounds

• In animal caps induced with activin, simultaneous activation of exogenous 5-hydroxytryptamine receptors inhibits both convergent extension movements associated with dorsal mesoderm induction and the expression of goosecoid, a dorsal-specific gene, but is without effect on expression of a 149 generic mesodermal marker, Xbra [13].
• In contrast, gsc shows strong superinduction in the presence of activin and CHX, and can be induced in animal explants by CHX alone [14].

Regulatory relationships of goosecoid

• Xwnt-8 can activate goosecoid only in the deep marginal zone, i.e., in the region in which this organizer-specific homeobox gene is normally expressed on the dorsal side [5].
• However, it was found that the beta-catenin pathway regulated the expression of both endogenous goosecoid, and a goosecoid promoter construct, in a cell non-autonomous manner [15].
• We show that the inability of Xbra to induce goosecoid is imposed by an N-terminal domain that interacts with the C-terminal MH2 domain of Smad1, a component of the BMP signal transduction pathway [16].

Other interactions of goosecoid

• Mesodermal patterning by a gradient of the vertebrate homeobox gene goosecoid [10].
• The maternal Xenopus beta-catenin signaling pathway, activated by frizzled homologs, induces goosecoid in a cell non-autonomous manner [15].
• Xlim-1 and LIM domain binding protein 1 cooperate with various transcription factors in the regulation of the goosecoid promoter [17].
• This study analyzes the function of the homeobox gene goosecoid in Xenopus development [18].
• Ectopic expression of BMP-4 RNA reduces goosecoid and forkhead-1 transcription in whole embryos and in activin-treated animal cap explants [19].

Analytical, diagnostic and therapeutic context of goosecoid

• Lastly, microinjection of goosecoid mRNA into the ventral side of Xenopus embryos, where goosecoid is normally absent, leads to the formation of an additional complete body axis, including head structures and abundant notochordal tissue [18].
• Using early blastomere explants (16-128-cell stage) cultured until gastrula stages, we demonstrate by RT-PCR analysis that the expression of goosecoid (gsc), wnt-8 and brachyury (bra) is dependent on mesoderm induction [20].
• Transcripts of the dorsal lip specific homeobox gene, goosecoid, and alpha-cardiac actin were detectable by PCR amplification in the animal quartet with a protrusion, and alpha-cardiac actin mRNA was found by whole-mount in situ hybridization to be localized in the protrusion [21].

References