Molecular cloning and evolutional analysis of a mammalian homologue of theDistal-less 3(Dlx-3) homeobox gene

Abstract

We have cloned and sequenced a cDNA encoding the mammalian homologue of Distal‐less 3 (Dlx‐3) from a rat embryonic brain cDNA library. The primary structure of rat Dlx‐3 showed a cDNA with an open reading frame of 290 amino acids with a molecular weight of 31 kDa harboring a homeodomain sequence characteristic of the Distal‐less homoeobox gene. In addition to the highly conserved homeodomain sequence, we newly found the consensus motifs in the N‐terminal and C‐terminal region, which were specifically conserved among Distal‐less members of different species. Phylogenetic analysis of the Distal‐less homeodomain sequence also showed a possible association between the sequence similarities in the homeodomain and the spatial specifications of homeobox genes expressed in the developing central nervous system.