Cloning and expression pattern of lbx3, a novel chick homeobox gene

The Drosophila melanogaster genes, ladybird early (lbe) and ladybird late (lbl), encode transcriptional regulators, which play an important role in neurogenesis, myogenesis and cardiogenesis. Here, we report an isolation of a novel ladybird family homeobox gene (lbx3) and its expression during chick development. The open reading frame of lbx3 encodes a predicted protein of 213 amino acids including a homeodomain, a PST motif and a nuclear localization signal. The homeodomain of lbx3 protein has 80% identities with the chick and mouse lbx1 homeodomains, and 75% identity with the mouse lbx2 homeodomain. Both lbx1 and lbx3 are expressed in prospective hypaxial myoblasts at cervical and limb level. In addition, lbx3 transcripts are detected in the medial dermomyotomal lips of somites of all axial levels at stage 23, but not detected in the neural tube.