Two Nkx-3-related genes are expressed in the adult and regenerating central nervous system of the urodele Pleurodeles waltl

We report the isolation and characterization of two NK-3-related genes (PwN kx-3.2 and PwNkx-3.3) and their expression patterns during embryonic develo pment, in the adult CNS, and during tail regeneration in the urodele Pleuro deles waltl. PwNkx-3.2 is the ortholog of the mouse and Xenopus genes, Bapx 1 and Xbap, but PwNkx-3.3 has no known homologue in any other vertebrate. We demonstrate that PwNkx-3.2 a nd PwNkx-3.3 exhibit graded axial expressio n patterns in adult spinal cord. During tail regeneration, the two genes ar e expressed in the wound epidermis, the regenerating muscle masses, the reg enerating neural tube, the spinal ganglia, and the cartilage rod. The spati al distribution of transcripts in the CNS suggests that these genes could p articipate in maintaining the position information along the anteroposterio r axis and may explain the ability of the adult CNS to regenerate. During t ail regeneration, both genes could be implicated in the reformation of: the axial skeleton. (C) 1999 Wiley-Liss, Inc.