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.
???displayArticle.abstract???
Here we show that Bmp signaling is necessary and sufficient for the specification of ventral endoderm in Xenopus embryos. Overexpression of Bmp4 in ectoderm induces markers of endoderm, including Sox17beta, Mixer, and VegT, but cannot induce the expression of the dorsoanterior markers, Xhex and Cerberus. Furthermore, knockdown approaches using overexpression of Bmp antagonists and morpholinos designed against Bmp4, Bmp2, and Bmp7 demonstrate that Bmp signaling is critical for ventral, but not dorsoanterior endoderm formation. This activity is not simply a result of embryonic dorsalization as markers for dorsal endoderm are not expanded. We further show that endodermal cells of either ventral or dorsal character do not form when both Wnt and Bmp signals are abolished. Overall, this report strongly suggests that Bmp plays an essential role in ventral endoderm specification.
Figure 3. Bmp antagonists disrupt early endoderm formation. One-cell embryos were injected vegetally with mRNA encoding the following Bmp Antagonists. B: DN-Alk3 (0.5 ng). C: Chordin (0.5 ng). D: Noggin (0.5 ng). The embryos were assayed by in situ hybridization with a probe for Sox17 beta at stage 10.5. A: A control injected with water. F-J: Two-cell-stage embryos were injected vegetally with 200 pg of lacZ mRNA, and mRNA for Chordin or Noggin as indicated. Embryos were fixed at stage 11, stained for lacZ using red gal substrate, and analyzed for Sox17 beta expression.
Figure 4. Bmp signaling is essential for endoderm formation in Xenopus. X. tropicalis embryos were injected at the two-cell stage with 10 ng per blastomere of each MO indicated, then analyzed for expression of Sox17 alpha (A, B) or Mixer (B) at stage 10.5. Miniruby fluorescent dextran was used as a tracer for MO injection. In B, a subset of MO-injected embryos were re-injected in one ventralblastomere at the 4-cell stage with 0.5 ng of mouse Bmp4. Nuclear beta -galactosidase (red) was used as a tracer. C: Triple Bmp morphant embryos were also analyzed for expression of Xbra, Derriere, Myf5, and Vent2.
Figure 5. Combination of Wnt and Bmp signaling is required for endoderm formation. X. tropicalis embryos were injected with 10 ng per blastomere of each MO indicated at the 2-cell stage, then analyzed at stage 10.5 for expression of the general endoderm markers Sox17 alpha and Mixer, or the dorsoanterior endoderm markers Cerberus and Xhex.
Agius,
Endodermal Nodal-related signals and mesoderm induction in Xenopus.
2000, Pubmed,
Xenbase
Agius,
Endodermal Nodal-related signals and mesoderm induction in Xenopus.
2000,
Pubmed
,
Xenbase
Beppu,
BMP type II receptor is required for gastrulation and early development of mouse embryos.
2000,
Pubmed
Bouwmeester,
Cerberus is a head-inducing secreted factor expressed in the anterior endoderm of Spemann's organizer.
1996,
Pubmed
,
Xenbase
Condie,
Posterior expression of a homeobox gene in early Xenopus embryos.
1987,
Pubmed
,
Xenbase
Costa,
Novel gene expression domains reveal early patterning of the Xenopus endoderm.
2003,
Pubmed
,
Xenbase
Dale,
BMP signalling in early Xenopus development.
1999,
Pubmed
,
Xenbase
Davis,
BMP receptor IA is required in the mammalian embryo for endodermal morphogenesis and ectodermal patterning.
2004,
Pubmed
De Robertis,
Dorsal-ventral patterning and neural induction in Xenopus embryos.
2004,
Pubmed
,
Xenbase
Dosch,
Bmp-4 acts as a morphogen in dorsoventral mesoderm patterning in Xenopus.
1997,
Pubmed
,
Xenbase
Engleka,
VegT activation of Sox17 at the midblastula transition alters the response to nodal signals in the vegetal endoderm domain.
2001,
Pubmed
,
Xenbase
Faure,
Endogenous patterns of TGFbeta superfamily signaling during early Xenopus development.
2000,
Pubmed
,
Xenbase
Graff,
Studies with a Xenopus BMP receptor suggest that ventral mesoderm-inducing signals override dorsal signals in vivo.
1994,
Pubmed
,
Xenbase
Harland,
Formation and function of Spemann's organizer.
1997,
Pubmed
Harland,
In situ hybridization: an improved whole-mount method for Xenopus embryos.
1991,
Pubmed
,
Xenbase
Hawley,
Disruption of BMP signals in embryonic Xenopus ectoderm leads to direct neural induction.
1995,
Pubmed
,
Xenbase
Heasman,
Beta-catenin signaling activity dissected in the early Xenopus embryo: a novel antisense approach.
2000,
Pubmed
,
Xenbase
Hemmati-Brivanlou,
Ventral mesodermal patterning in Xenopus embryos: expression patterns and activities of BMP-2 and BMP-4.
1995,
Pubmed
,
Xenbase
Henry,
Mixer, a homeobox gene required for endoderm development.
1998,
Pubmed
,
Xenbase
Hsu,
The Xenopus dorsalizing factor Gremlin identifies a novel family of secreted proteins that antagonize BMP activities.
1998,
Pubmed
,
Xenbase
Hudson,
Xsox17alpha and -beta mediate endoderm formation in Xenopus.
1997,
Pubmed
,
Xenbase
Jones,
Nodal-related signals induce axial mesoderm and dorsalize mesoderm during gastrulation.
1995,
Pubmed
,
Xenbase
Jones,
An anterior signalling centre in Xenopus revealed by the homeobox gene XHex.
1999,
Pubmed
,
Xenbase
Jones,
DVR-4 (bone morphogenetic protein-4) as a posterior-ventralizing factor in Xenopus mesoderm induction.
1992,
Pubmed
,
Xenbase
Khokha,
Techniques and probes for the study of Xenopus tropicalis development.
2002,
Pubmed
,
Xenbase
Kofron,
Mesoderm induction in Xenopus is a zygotic event regulated by maternal VegT via TGFbeta growth factors.
1999,
Pubmed
,
Xenbase
Kofron,
The role of Mixer in patterning the early Xenopus embryo.
2004,
Pubmed
,
Xenbase
Kurata,
Visualization of endogenous BMP signaling during Xenopus development.
2001,
Pubmed
,
Xenbase
Lane,
The origins of primitive blood in Xenopus: implications for axial patterning.
1999,
Pubmed
,
Xenbase
Mead,
BMP-4-responsive regulation of dorsal-ventral patterning by the homeobox protein Mix.1.
1996,
Pubmed
,
Xenbase
Mishina,
Bmpr encodes a type I bone morphogenetic protein receptor that is essential for gastrulation during mouse embryogenesis.
1995,
Pubmed
Myers,
Characterization of mouse Rsk4 as an inhibitor of fibroblast growth factor-RAS-extracellular signal-regulated kinase signaling.
2004,
Pubmed
,
Xenbase
Newman,
The XHex homeobox gene is expressed during development of the vascular endothelium: overexpression leads to an increase in vascular endothelial cell number.
1997,
Pubmed
,
Xenbase
Nishimatsu,
Genes for bone morphogenetic proteins are differentially transcribed in early amphibian embryos.
1992,
Pubmed
,
Xenbase
Osada,
Xenopus nodal-related signaling is essential for mesendodermal patterning during early embryogenesis.
1999,
Pubmed
,
Xenbase
Peng,
Xenopus laevis: Practical uses in cell and molecular biology. Solutions and protocols.
1991,
Pubmed
,
Xenbase
Poulain,
Zebrafish endoderm formation is regulated by combinatorial Nodal, FGF and BMP signalling.
2006,
Pubmed
Sasai,
Endoderm induction by the organizer-secreted factors chordin and noggin in Xenopus animal caps.
1996,
Pubmed
,
Xenbase
Sasai,
Xenopus chordin: a novel dorsalizing factor activated by organizer-specific homeobox genes.
1994,
Pubmed
,
Xenbase
Schmidt,
Localized BMP-4 mediates dorsal/ventral patterning in the early Xenopus embryo.
1995,
Pubmed
,
Xenbase
Shivdasani,
Molecular regulation of vertebrate early endoderm development.
2002,
Pubmed
,
Xenbase
Sinner,
Sox17 and beta-catenin cooperate to regulate the transcription of endodermal genes.
2004,
Pubmed
,
Xenbase
Smith,
Expression cloning of noggin, a new dorsalizing factor localized to the Spemann organizer in Xenopus embryos.
1992,
Pubmed
,
Xenbase
Smith,
Expression of a Xenopus homolog of Brachyury (T) is an immediate-early response to mesoderm induction.
1991,
Pubmed
,
Xenbase
Suzuki,
Xenopus msx1 mediates epidermal induction and neural inhibition by BMP4.
1997,
Pubmed
,
Xenbase
Suzuki,
Mesoderm induction by BMP-4 and -7 heterodimers.
1997,
Pubmed
,
Xenbase
Suzuki,
A truncated bone morphogenetic protein receptor affects dorsal-ventral patterning in the early Xenopus embryo.
1994,
Pubmed
,
Xenbase
Tiso,
BMP signalling regulates anteroposterior endoderm patterning in zebrafish.
2002,
Pubmed
Turner,
Expression of achaete-scute homolog 3 in Xenopus embryos converts ectodermal cells to a neural fate.
1994,
Pubmed
,
Xenbase
Wieser,
GS domain mutations that constitutively activate T beta R-I, the downstream signaling component in the TGF-beta receptor complex.
1995,
Pubmed
Wilson,
Mesodermal patterning by an inducer gradient depends on secondary cell-cell communication.
1994,
Pubmed
,
Xenbase
Winnier,
Bone morphogenetic protein-4 is required for mesoderm formation and patterning in the mouse.
1995,
Pubmed
Xanthos,
Maternal VegT is the initiator of a molecular network specifying endoderm in Xenopus laevis.
2001,
Pubmed
,
Xenbase
Zhang,
The role of maternal VegT in establishing the primary germ layers in Xenopus embryos.
1998,
Pubmed
,
Xenbase
Zorn,
Anterior endomesoderm specification in Xenopus by Wnt/beta-catenin and TGF-beta signalling pathways.
1999,
Pubmed
,
Xenbase