Expression of two members of the Wnt family during mouse development--restricted temporal and spatial patterns in the developing neural tube.
The Wnt gene family encodes a group of cysteine-rich proteins implicated in intercellular signaling during several stages of vertebrate development. This family includes Wnt-1 and Wnt-3, both discovered as activated oncogenes in mouse mammary tumors. Here we describe the molecular cloning of an additional member of the Wnt family, called Wnt-3A, and the spatial and temporal expression pattern of this gene as well as that of its close relative Wnt-3. The putative amino acid sequences of both proteins are almost 90% identical, but in situ hybridization to mouse embryo sections showed highly restricted patterns of expression of Wnt-3 and Wnt-3A, largely in separate areas in the developing nervous system. In the spinal cord Wnt-3 was expressed at low levels in the alar laminae and in the ventral horns, whereas Wnt-3A expression was confined to the roof plate. In the developing brain Wnt-3 was expressed broadly across the dorsal portion of the neural tube with a rostral boundary of expression at the diencephalon. In contrast, Wnt-3A was expressed in a narrow region very close to the midline; expression extended into the bifurcating telencephalon, in a highly localized fashion. Both Wnt-3 and Wnt-3A were expressed in the ectoderm, and Wnt-3A was also expressed in the periumbilical mesenchyme. Characteristic expression patterns of these two closely related genes suggest that Wnt-3 and Wnt-3A play distinct roles in cell-cell signaling during morphogenesis of the developing neural tube.
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Howard Hughes Medical Institute, Beckman Center, Stanford University, California 94305.
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D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002490:Central Nervous System / Q000196:embryology* / Q000378:metabolism; D003001:Cloning, Molecular; D005260:Female; D015870:Gene Expression; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D005810:Multigene Family; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics; D009857:Oncogenes; D011247:Pregnancy; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D015398:Signal Transduction; D051153:Wnt Proteins; D060508:Wnt3 Protein; D060509:Wnt3A Protein
D009363:Neoplasm Proteins; D011506:Proteins; D051153:Wnt Proteins; D060508:Wnt3 Protein; C555508:Wnt3 protein, mouse; D060509:Wnt3A Protein; C555511:Wnt3a protein, mouse