VENTRAL NEURAL CADHERIN, A NOVEL CADHERIN EXPRESSED IN A SUBSET OF NEURAL TISSUES IN THE ZEBRAFISH EMBRYO

Cadherins are calcium-binding transmembrane glycoproteins that are imp ortant mediators of cell-cell association. Here we describe a novel me mber of this gene family, zebrafish ventral neural cadherin (VN-cad). Multiple VN-cad transcripts are first detectable by Northern blots at 60% epiboly. In the developing neural tube, VN-cad RNA is first found in the neuroectoderm, directly above the notochord, and later was loca lized to the neural keel. At the 20-somite stage, VN-cad transcripts a re confined to the ventral neural tube, otic vesicle, midbrain, and di encephelon. Transcription of VN-cad RNA continues in adult fish. The e mbryonic pattern of expression is not significantly disrupted in cyclo ps or no tail mutants, which lack the floor plate and notochord, respe ctively. Therefore, neither of these structures is absolutely required for VN-cad expression. The localized pattern of VN-cad expression sug gests a possible role for this adhesion molecule in the initial format ion and subsequent differentiation of the central nervous system. (C) 1996 Wiley-Liss, Inc.