THE ZEBRAFISH PAX3 AND PAX7 HOMOLOGS ARE HIGHLY CONSERVED, ENCODE MULTIPLE ISOFORMS AND SHOW DYNAMIC SEGMENT-LIKE EXPRESSION IN THE DEVELOPING BRAIN

This study describes the isolation and characterization of zebrafish h omologues of the mammalian Pax3 and Pax7 genes. The proteins encoded b y both zebrafish genes are highly conserved (>83%) relative to the kno wn mammalian sequences. Also the neural expression patterns during emb ryogenesis are very similar to the murine homologues. However, observe d differences in neural crest and mesodermal expression relative to ma mmals could reflect some functional divergence in the development of t hese tissues. For the zebrafish Pax7 protein we report the first full- length amino acid sequences in vertebrates and show the existence of t hree additional isoforms which have truncations in the homeodomain and /or the C-terminal region. These novel variants provide evidence for a dditional isoform diversity of vertebrate Pax proteins. (C) 1998 Elsev ier Science Ireland Ltd.