The Xvent-2 homeobox gene is part of the BMP-4 signalling pathway controlling [correction of controling] dorsoventral patterning of Xenopus mesoderm.
We describe a novel Xenopus homeobox gene, Xvent-2, which together with the previously identified homeobox gene Xvent-1, defines a novel class of homeobox genes. vent genes are related by sequence homology, expression pattern and gain-of-function phenotype. Evidence is presented for a role of Xvent-2 in the BMP-4 pathway involved in dorsoventral patterning of mesoderm. (1) Xvent-2 is expressed in regions that also express BMP-4. (2) Xvent-2 and BMP-4 interact in a positive feedback loop. (3) Xvent-2 ventralizes dorsal mesoderm in a dose-dependent manner resulting in phenoytpes ranging from microcephaly to Bauchstück pieces, as does BMP-4. (4) Like BMP-4 and gsc, Xvent-2 and gsc are able to interact in a crossregulatory loop to suppress each other. (5) Microinjection of Xvent-2 mRNA can rescue dorsalization by a dominant-negative BMP-4 receptor. The results suggest that Xvent-2 functions in the BMP-4 signalling pathway that antagonizes the Spemann organizer.
Division of Molecular Embryology, Deutsches Krebsforschungszentrum, Heidelberg, Germany.
D
D
Onichtchouk
V
V
Gawantka
R
R
Dosch
H
H
Delius
K
K
Hirschfeld
C
C
Blumenstock
C
C
Niehrs
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D052004:Bone Morphogenetic Protein Receptors; D019485:Bone Morphogenetic Proteins / Q000378:metabolism*; D002454:Cell Differentiation; D003001:Cloning, Molecular; D018076:DNA, Complementary; D015870:Gene Expression; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism*; D008648:Mesoderm; D008845:Microinjections; D008969:Molecular Sequence Data; D009672:Notochord / Q000166:cytology; D011956:Receptors, Cell Surface; D017978:Receptors, Growth Factor; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors; D014981:Xenopus / Q000196:embryology*; D029867:Xenopus Proteins
D019485:Bone Morphogenetic Proteins; D018076:DNA, Complementary; D018398:Homeodomain Proteins; D011956:Receptors, Cell Surface; D017978:Receptors, Growth Factor; D014157:Transcription Factors; D029867:Xenopus Proteins; C099992:ventx2.1 protein, Xenopus; D052004:Bone Morphogenetic Protein Receptors