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.
The dorsal-specific homeobox gene goosecoid (gsc) and the bone morphogenetic protein 4 gene (BMP-4) are expressed in complementary regions of the Xenopus gastrula. Injection of gsc mRNA dorsalizes ventral mesodermal tissue and can induce axis formation in normal and UV-ventralized embryos. On the other hand, BMP-4 mRNA injection, which has a strong ventralizing effect on whole embryos, has been implicated in ventralization by UV, and can rescue tail structures in embryos dorsalized by LiCl. The above-mentioned putative roles for BMP-4 and gsc are based on gain-of-function experiments. In order to determine the in vivo role of these two genes in the patterning of the Xenopus mesoderm during gastrulation, partial loss-of-function experiments were performed using antisense RNA injections. Using marker genes that are expressed early in gastrulation, we show that antisense gsc RNA has a ventralizing effect on embryos, whereas antisense BMP-4 RNA dorsalizes mesodermal tissue. These loss-of-function studies also show a requirement for gsc and BMP-4 in the dorsalization induced by LiCl and in the ventralization generated by UV irradiation, respectively. Thus, both gain- and loss-of-function results for gsc and BMP-4 support the view that these two genes are necessary components of the dorsal and ventral patterning pathways in Xenopus embryos.
D000818:Animals; D001483:Base Sequence; D019485:Bone Morphogenetic Proteins; D005775:Gastrula / Q000378:metabolism / Q000473:pathology; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox; D008648:Mesoderm / Q000378:metabolism / Q000473:pathology; D008969:Molecular Sequence Data; D011506:Proteins / Q000235:genetics*; D016372:RNA, Antisense / Q000494:pharmacology*; D014981:Xenopus / Q000196:embryology* / Q000235:genetics* / Q000378:metabolism
D019485:Bone Morphogenetic Proteins; D011506:Proteins; D016372:RNA, Antisense