Isolation and characterization of a developmentally regulated homeobox sequence in the Mexican axolotl Ambystoma...

A homeobox-containing genomic DNA fragment was isolated from the Mexican axolotl. This clone was obtained from a partial genomic library enriched for sequences that cross-hybridized with the Drosophila Antp homeobox under low stringency hybridization conditions. DNA sequence analysis revealed that this sequence (Ahox1) was 66% homologous to the Antp homeobox sequence and was most closely related to the mouse Hox-1.6 (84% identity) and Drosophila lab (79% identity) homeobox sequences. Several cross-hybridizing fragments to Ahox1 were detected in both mouse and axolotl genomic DNA. This sequence was also shown to be conserved in other Ambystoma species. Northern blot analysis revealed that genes containing this sequence are developmentally regulated. Transcripts hybridizing to the Ahox1 homeobox probe were detected during the neurula and tail bud stages of development.