Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
EMBO J
2007 Jun 20;2612:2955-65. doi: 10.1038/sj.emboj.7601705.
Show Gene links
Show Anatomy links
The opposing homeobox genes Goosecoid and Vent1/2 self-regulate Xenopus patterning.
Sander V
,
Reversade B
,
De Robertis EM
.
???displayArticle.abstract???
We present a loss-of-function study using antisense morpholino (MO) reagents for the organizer-specific gene Goosecoid (Gsc) and the ventral genes Vent1 and Vent2. Unlike in the mouse Gsc is required in Xenopus for mesodermal patterning during gastrulation, causing phenotypes ranging from reduction of head structures-including cyclopia and holoprosencephaly-to expansion of ventral tissues in MO-injected embryos. The overexpression effects of Gsc mRNA require the expression of the BMP antagonist Chordin, a downstream target of Gsc. Combined Vent1 and Vent2 MOs strongly dorsalized the embryo. Unexpectedly, simultaneous depletion of all three genes led to a rescue of almost normal development in a variety of embryological assays. Thus, the phenotypic effects of depleting Gsc or Vent1/2 are caused by the transcriptional upregulation of their opposing counterparts. A principal function of Gsc and Vent1/2 homeobox genes might be to mediate a self-adjusting mechanism that restores the basic body plan when deviations from the norm occur, rather than generating individual cell types. The results may shed light on the molecular mechanisms of genetic redundancy.
Figure 1. Gsc knockdown in Xenopus embryos causes loss of head structures and affects patterning of the AP and DV axes. (A) Gsc marks Spemann organizerendomesoderm at early gastrula. (B) Gsc MO targets both pseudoalleles of the X. laevis Gsc gene. (C–I) Gsc MO injection (136 ng total) causes loss of head structures, marked by Otx2 (forebrain), Six3 and Rx2a (forebrain and eyes), and En2 (midbrain/hindbrain border) (n=106; Supplementary Table I). Expression of the ventral marker Szl is reduced anteriorly and expanded posteriorly in the ventral blood island. (E) Co-injection of mGsc mRNA (200 pg total, radial injection) rescues the Gsc MO phenotype (n=78). (H, I) Knockdown of Gsc reduces head size and affects patterning of the posterior somites, including loss of MyoD expression at the tip of the tail (arrows). (J, K) Moderately affected embryos survive until tadpole stage and have cyclopic eyes (indicating holoprosencephaly) and no mouth opening.
Figure 2. The dorsalizing effects of mGsc mRNA injection require Chd. (A–E) Gsc MO reduces Chd expression at gastrula 2.5-fold, whereas overexpression of mGsc mRNA greatly expands Chd expression. (F–H) Injection of 50 pg mGsc mRNA into one ventral blastomere at the four-cell stage leads to a range of dorsalized phenotypes, of which 50% develop secondary axes (38% partial; 12% complete with eyes, notochords, and cement glands). (I, J) Co-injection of Chd MO (34 ng) prevents second axis induction and dorsalization by mGsc mRNA in 97% of the embryos. (K, L) mGsc mRNA microinjection (200 pg total) induces Chd expression in UV-ventralized embryos at gastrula. (M–O) The rescue of head (Otx2) and pan-neural marker (Sox2) in UV embryos by mGsc overexpression (n=54) has a complete requirement for Chd (co-injection of 136 ng Chd MO; n=59).
Figure 3. Gsc is required for secondary neural induction and mesoderm patterning in Activin-treated animal cap explants. (A) Experimental design (n=15 or more per experimental set) (B, C) Untreated animal caps develop into atypical epidermis, whereas Activin treatment leads to elongation and brain formation, visualized by Otx2 at the anterior pole (arrows). In addition, Otx2 expression in anterior endoderm can be seen in one of the explants (arrowhead). (D, E) Gsc-depleted caps elongate after treatment with Activin, but lack Otx2 neural staining. (F, G) Chd-depleted caps treated with Activin are unable to elongate, confirming the requirement of Chd for dorsal mesoderm and neural induction by Activin (Oelgeschläger et al, 2003). Insets show whole sibling embryos. (H) Quantitative RT–PCRs showing genes affected by depletion of Gsc include markers of anteriorCNS, organizer, somites, and ventral mesoderm. Note that Vent1 expression is increased more than 20-fold by Gsc knockdown.
Figure 4. Double depletion of Vent1 and Vent2 causes severe dorsalization of the embryo. (A–D) Injection of either Vent1 or Vent2 MO expands the neural plate at neurula stage (insets), but only the combination of both MOs strongly dorsalizes tailbud stage embryos, with shortened body axes and large heads and cement glands (n=122; Supplementary Table I). (E, F) Vent1/2 depletion leads to transcriptional upregulation of Gsc (hemisections at stage 10; n=15) and Chd (insets in panels E and F; whole embryos, vegetal view; n=18). (G, H) Loss of Gsc increases Vent1 and Vent2 expression (hemisections at stage 10; n=21 and 15) (I) Quantitative RT–PCR analyses showing 3- to 4-fold upregulation of the organizer genes Gsc, Chd, and Admp in animal caps at gastrula stage after Vent1/2 depletion.
Figure 5. Gsc is required for the dorsalization caused by Vent1/2 knockdown. (A–I) Co-injection of Gsc MO restores normal pattern in Vent1/2-depleted whole embryos (n=53; Supplementary Table I). At the neurula stage, knockdown of Vent1/2/Gsc reduces the neural plate (Sox2) back to normal size (insets in panels A–C). In addition, the expansion of the cement gland and midbrain in Vent1/2 morphants is rescued in triple knockdown embyros (insets in panels G–I). Note that blood formation (Scl) is not rescued in the triple depletions (I). All MOs were injected at the same dose (45 ng each). (J) The upregulation of Chd expression by Vent1/2 MO is restored to control levels in Vent1/2/Gsc-depleted animal caps at gastrula stage. (K) Expression of Szl is downregulated by Vent1/2 MO, but restored to normal levels when Gsc is also depleted.
Figure 6. Knockdown of Gsc and Vent1/2 restores normal development of dorsal and ventral half-embryos (n=52 or more per experimental set). (A) Embryos were bisected into dorsal and ventral halves at blastula stage. (B) Control sibling at the same magnification as the other panels. (C, D) Bisectioned control embryos form smaller but well-proportioned dorsal half-embryos, whereas ventral halves differentiate into belly-pieces that express HoxB9 in the ventral mesoderm (Wright et al, 1990) but are devoid of neural tissue, as indicated by the lack of Sox2 expression (inset). (E, F) Gsc depletion (136 ng MO) causes a reduction of the head in dorsal halves, whereas ventral halves are not affected. (G, H) Dorsal halves of Vent1- and Vent2-depleted embryos (45 ng each) are dorsalized, but retain overall DV patterning. The corresponding ventral halves are strongly dorsalized, including expression of spinal cord (HoxB9), brain (Krox20, Six3), and pan-neural Sox2 marker (inset). (I, J) Remarkably, both halves of triple knockdown embryos (45 ng each) develop as the uninjected control half-embryos.
Figure 7. Model of regulatory mechanisms for pattern formation at gastrula. In the dorsal center, Activin/Nodal signals phosphorylate Smad2/3 to activate Gsc expression. The expansion of Chd and ADMP can also be achieved by Gsc-independent pathways. In the ventral center, BMP4/7 signals phosphorylate Smad1/5/8 and lead to the expression of Vent1/2. BMP4 is also able to activate ventral center secreted proteins by Vent-independent mechanisms. The function of Gsc and Vent is to regulate each other, providing an intracellular compensatory mechanism that works in concert with the extracellular networks of growth factors and their antagonists.
Ault,
A novel homeobox gene PV.1 mediates induction of ventral mesoderm in Xenopus embryos.
1996, Pubmed,
Xenbase
Ault,
A novel homeobox gene PV.1 mediates induction of ventral mesoderm in Xenopus embryos.
1996,
Pubmed
,
Xenbase
Belo,
The prechordal midline of the chondrocranium is defective in Goosecoid-1 mouse mutants.
1998,
Pubmed
Blum,
Gastrulation in the mouse: the role of the homeobox gene goosecoid.
1992,
Pubmed
,
Xenbase
Cho,
Molecular nature of Spemann's organizer: the role of the Xenopus homeobox gene goosecoid.
1991,
Pubmed
,
Xenbase
Danilov,
Negative autoregulation of the organizer-specific homeobox gene goosecoid.
1998,
Pubmed
,
Xenbase
De Robertis,
Spemann's organizer and self-regulation in amphibian embryos.
2006,
Pubmed
Fainsod,
On the function of BMP-4 in patterning the marginal zone of the Xenopus embryo.
1994,
Pubmed
,
Xenbase
Ferreiro,
Antimorphic goosecoids.
1998,
Pubmed
,
Xenbase
Filosa,
Goosecoid and HNF-3beta genetically interact to regulate neural tube patterning during mouse embryogenesis.
1997,
Pubmed
Gawantka,
Antagonizing the Spemann organizer: role of the homeobox gene Xvent-1.
1995,
Pubmed
,
Xenbase
Goriely,
A functional homologue of goosecoid in Drosophila.
1996,
Pubmed
,
Xenbase
Hahn,
Drosophila goosecoid participates in neural development but not in body axis formation.
1996,
Pubmed
,
Xenbase
Hartwell,
The Spemann organizer gene, Goosecoid, promotes tumor metastasis.
2006,
Pubmed
Heasman,
Morpholino oligos: making sense of antisense?
2002,
Pubmed
,
Xenbase
Henningfeld,
Autoregulation of Xvent-2B; direct interaction and functional cooperation of Xvent-2 and Smad1.
2002,
Pubmed
,
Xenbase
Imai,
The homeobox genes vox and vent are redundant repressors of dorsal fates in zebrafish.
2001,
Pubmed
,
Xenbase
Kappen,
Early evolutionary origin of major homeodomain sequence classes.
1993,
Pubmed
Karaulanov,
Transcriptional regulation of BMP4 synexpression in transgenic Xenopus.
2004,
Pubmed
,
Xenbase
Kawahara,
Functional interaction of vega2 and goosecoid homeobox genes in zebrafish.
2000,
Pubmed
Kawahara,
Antagonistic role of vega1 and bozozok/dharma homeobox genes in organizer formation.
2000,
Pubmed
Klein,
The first cleavage furrow demarcates the dorsal-ventral axis in Xenopus embryos.
1987,
Pubmed
,
Xenbase
Ladher,
Xom: a Xenopus homeobox gene that mediates the early effects of BMP-4.
1996,
Pubmed
,
Xenbase
Latinkic,
Goosecoid and mix.1 repress Brachyury expression and are required for head formation in Xenopus.
1999,
Pubmed
,
Xenbase
Lee,
Embryonic dorsal-ventral signaling: secreted frizzled-related proteins as inhibitors of tolloid proteinases.
2006,
Pubmed
,
Xenbase
Lewis,
Genetic interaction of Gsc and Dkk1 in head morphogenesis of the mouse.
2007,
Pubmed
Lim,
Bar homeodomain proteins are anti-proneural in the Drosophila eye: transcriptional repression of atonal by Bar prevents ectopic retinal neurogenesis.
2003,
Pubmed
Melby,
Regulation of dorsal gene expression in Xenopus by the ventralizing homeodomain gene Vox.
1999,
Pubmed
,
Xenbase
Melby,
Patterning the early zebrafish by the opposing actions of bozozok and vox/vent.
2000,
Pubmed
,
Xenbase
Moretti,
Molecular cloning of a human Vent-like homeobox gene.
2001,
Pubmed
,
Xenbase
Niehrs,
The Spemann organizer and embryonic head induction.
2001,
Pubmed
Niehrs,
Synexpression groups in eukaryotes.
1999,
Pubmed
,
Xenbase
Niehrs,
The homeobox gene goosecoid controls cell migration in Xenopus embryos.
1993,
Pubmed
,
Xenbase
Niehrs,
Mesodermal patterning by a gradient of the vertebrate homeobox gene goosecoid.
1994,
Pubmed
,
Xenbase
Oelgeschläger,
Chordin is required for the Spemann organizer transplantation phenomenon in Xenopus embryos.
2003,
Pubmed
,
Xenbase
Onichtchouk,
The Xvent-2 homeobox gene is part of the BMP-4 signalling pathway controlling [correction of controling] dorsoventral patterning of Xenopus mesoderm.
1996,
Pubmed
,
Xenbase
Onichtchouk,
Requirement for Xvent-1 and Xvent-2 gene function in dorsoventral patterning of Xenopus mesoderm.
1998,
Pubmed
,
Xenbase
Papalopulu,
A Xenopus gene, Xbr-1, defines a novel class of homeobox genes and is expressed in the dorsal ciliary margin of the eye.
1996,
Pubmed
,
Xenbase
Polli,
A study of mesoderm patterning through the analysis of the regulation of Xmyf-5 expression.
2002,
Pubmed
,
Xenbase
Rastegar,
Transcriptional regulation of Xvent homeobox genes.
1999,
Pubmed
,
Xenbase
Reig,
Functions of BarH transcription factors during embryonic development.
2007,
Pubmed
Reversade,
Regulation of ADMP and BMP2/4/7 at opposite embryonic poles generates a self-regulating morphogenetic field.
2005,
Pubmed
,
Xenbase
Rivera-Pérez,
Goosecoid is not an essential component of the mouse gastrula organizer but is required for craniofacial and rib development.
1995,
Pubmed
,
Xenbase
Saito,
Mammalian BarH homologue is a potential regulator of neural bHLH genes.
1998,
Pubmed
,
Xenbase
Sander,
Xenopus brevican is expressed in the notochord and the brain during early embryogenesis.
2001,
Pubmed
,
Xenbase
Sasai,
Xenopus chordin: a novel dorsalizing factor activated by organizer-specific homeobox genes.
1994,
Pubmed
,
Xenbase
Schmidt,
Regulation of dorsal-ventral patterning: the ventralizing effects of the novel Xenopus homeobox gene Vox.
1996,
Pubmed
,
Xenbase
Schuler-Metz,
The homeodomain transcription factor Xvent-2 mediates autocatalytic regulation of BMP-4 expression in Xenopus embryos.
2000,
Pubmed
,
Xenbase
Seiliez,
FoxA3 and goosecoid promote anterior neural fate through inhibition of Wnt8a activity before the onset of gastrulation.
2006,
Pubmed
Steinbeisser,
Xenopus axis formation: induction of goosecoid by injected Xwnt-8 and activin mRNAs.
1993,
Pubmed
,
Xenbase
Steinbeisser,
The role of gsc and BMP-4 in dorsal-ventral patterning of the marginal zone in Xenopus: a loss-of-function study using antisense RNA.
1995,
Pubmed
,
Xenbase
Struhl,
Differing strategies for organizing anterior and posterior body pattern in Drosophila embryos.
1989,
Pubmed
Tissier-Seta,
Barx1, a new mouse homeodomain transcription factor expressed in cranio-facial ectomesenchyme and the stomach.
1995,
Pubmed
Trindade,
DNA-binding specificity and embryological function of Xom (Xvent-2).
1999,
Pubmed
,
Xenbase
Wright,
The Xenopus XIHbox 6 homeo protein, a marker of posterior neural induction, is expressed in proliferating neurons.
1990,
Pubmed
,
Xenbase
Yamada,
Targeted mutation of the murine goosecoid gene results in craniofacial defects and neonatal death.
1995,
Pubmed
Yao,
Goosecoid promotes head organizer activity by direct repression of Xwnt8 in Spemann's organizer.
2001,
Pubmed
,
Xenbase
Zhu,
Goosecoid regulates the neural inducing strength of the mouse node.
1999,
Pubmed