On the function of BMP-4 in patterning the marginal zone of the Xenopus embryo.
Bone morphogenetic protein 4 (BMP-4) is expressed in the ventral marginal zone of the gastrulating embryo. At late gastrula stage this gene is expressed in the ventral-most part of the slit blastopore and in tissues that derive from it. At tailbud stages BMP-4 is expressed in the spinal cord roof plate, neural crest, eye and auditory vesicle. The interactions of BMP-4 with dorsal genes such as goosecoid (gsc) and Xnot-2 were studied in vivo. In embryos ventralized by UV irradiation and suramin treatment, BMP-4 zygotic transcripts accumulate prematurely and the entire marginal zone expresses this gene. The patterning effect of BMP-4 on ventro-posterior development can be revealed by a sensitive assay involving the injection of BMP-4 mRNA in the ventral marginal zone of embryos partially dorsalized with LiCl, which leads to the complete rescue of trunk and tail structures. The experiments presented here argue that BMP-4 may act in vivo as a ventral signal for the proper patterning of the marginal zone, actively interacting with dorsal genes such as gsc and Xnot-2. A model is proposed in which the timing of expression of various marginal zone-specific genes plays a central role in patterning the mesoderm.
Fainsod
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A
Molecular Biology Institute, University of California, Los Angeles 90024-1737.
Steinbeisser
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De Robertis
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EM
D000818:Animals; D001483:Base Sequence; D019485:Bone Morphogenetic Proteins; D004268:DNA-Binding Proteins / Q000235:genetics; D004625:Embryo, Nonmammalian / Q000187:drug effects / Q000528:radiation effects; D004627:Embryonic Induction; D005775:Gastrula; D005786:Gene Expression Regulation / Q000187:drug effects / Q000528:radiation effects; D051956:Goosecoid Protein; D018398:Homeodomain Proteins; D018021:Lithium Chloride / Q000494:pharmacology; D008648:Mesoderm; D008969:Molecular Sequence Data; D011506:Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis*; D012097:Repressor Proteins; D013997:Time Factors; D014018:Tissue Distribution; D015534:Trans-Activators / Q000235:genetics; D014157:Transcription Factors; D014466:Ultraviolet Rays; D014981:Xenopus / Q000196:embryology*; D029867:Xenopus Proteins
D019485:Bone Morphogenetic Proteins; D004268:DNA-Binding Proteins; D051956:Goosecoid Protein; D018398:Homeodomain Proteins; C080209:Not protein, Xenopus; D011506:Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D029867:Xenopus Proteins; D018021:Lithium Chloride