fgfr3 and regionalization of anterior neural tube in zebrafish

Here we describe the isolation of the zebrafish fgfr3 gene, its structure a nd chromosomal location. Expression in wild type embryos occurs in the axia l mesoderm, the diencephalon, the anterior hindbrain and the anterior spina l cord. In the hindbrain, a differential expression of fgfr3 was detected a t several levels of intensity, with the highest expression in the posterior rhombomere 1 that is morphologically distinct from the anterior part, whic h develops into the cerebellum. Further, analysis of fgfr3 expression in mu tants deficient in the formation of the midbrain-hindbrain boundary (MHB), noi(-/-) and ace(-/-), demonstrated that in the absence of Pax2.1 and FGF8 activity, the expression domains of FGFR3 expand into the MHB, tegmentum, c erebellum and optic tectum, which are the affected structures in these muta nts. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.