Transcription of XLPOU3, a brain-specific gene, during Xenopus laevis early embryogenesis

XLPOU3 is a member of the Xenopus POU domain family of genes, encoding a class of homeodomain-containing transcription factors implicated in cell differentiation during development. Here we describe the isolation and characterisation of XLPOU3b, an allelic genomic counterpart of the XLPOU3 cDNA previously described (Baltzinger et al. (1992) Nucleic Acids Res. 20, 1993), and the spatio-temporal transcription patterns of this gene during development, as determined by Northern blotting and whole-mount in situ hybridisation. Like other genes encoding POU domains of class III, XLPOU3b is intronless. XLPOU3 and XLPOU3b proteins share 82% amino acid identity with the mammalian N-Oct-3/Brn-2 proteins. XLPOU3 mRNA, which is first detected at the neurula stage, is expressed in the developing brain and spinal cord. In addition, XLPOU3 transcription is observed in a restricted region of the auditory vesicle during development. The results suggest that XLPOU3 may participate in patterning the central nervous system during early Xenopus development.