Dorsal-ventral patterning and differentiation of noggin-induced neural tissue in the absence of mesoderm

• Published in: Development (Cambridge) Vol. 121; no. 6; pp. 1927 - 1935
• Main Authors: Knecht, A K, Good, P J, Dawid, I B, Harland, R M
• Format: Journal Article
• Language: English
• Published: England The Company of Biologists Limited 01-06-1995
• Subjects: Amino Acid Sequence; Animals; Carrier Proteins; Ectoderm - physiology; ELAV Proteins; Embryonic Induction; Freshwater; Gene Expression; Genes; Genetic Markers; Membrane Proteins - genetics; Molecular Sequence Data; Morphogenesis - genetics; Nerve Tissue Proteins - genetics; Nervous System - embryology; Proteins - genetics; Proteins - physiology; R-SNARE Proteins; Ribonucleoproteins - genetics; RNA-Binding Proteins - genetics; Xenopus - embryology; Xenopus - genetics; Xenopus laevis; Xenopus Proteins
• ISSN: 0950-1991; 1477-9129
• DOI: 10.1242/dev.121.6.1927

In Xenopus development, dorsal mesoderm is thought to play a key role in both induction and patterning of the nervous system. Previously, we identified a secreted factor, noggin, which is expressed in dorsal mesoderm and which can mimic that tissue's neural-inducing activity, without inducing mesoderm. Here the neural tissue induced in ectodermal explants by noggin is further characterized using four neural-specific genes: two putative RNA-binding proteins, nrp-1 and etr-1; the synaptobrevin sybII; and the lipocalin cpl-1. First we determine the expression domain of each gene during embryogenesis. Then we analyze expression of these genes in noggin-treated explants. All markers, including the differentiated marker sybII, are expressed in noggin-induced neural tissue. Furthermore, cpl-1, a marker of dorsal brain, and etr-1, a marker absent in much of the dorsal forebrain, are expressed in non-overlapping territories within these explants. We conclude that the despite the absence of mesoderm, noggin-induced neural tissue shows considerable differentiation and organization, which may represent dorsal-ventral patterning of the forebrain.