DIFFERENTIAL REGULATION OF HOX C6 IN THE APPENDAGES OF ADULT URODELES AND ANURANS

Abstract Morphogenesis and pattern formation are biological processes that rely on the expression of positional determinants to divide the embryo into compartments. Hox genes are among the selector genes that direct the mechanism of positional information. Here we report the molecular structure and pattern of expression of a new Hox C6 transcript in the adult newt. Molecular analysis showed that the gene transcribes a long primary transcript in both limb and tail regeneration territories and subsequently uses maturation events to produce two RNAs that share the same DNA binding domain and differ in their 5′ extremity. Both RNAs were found in the limb and showed a proximal-distal gradient of expression. The tail sample showed accumulation of only one Hox C6 transcript. These results suggest that both transcriptional and post-transcriptional regulations are involved in the appendage-specific expression of Hox C6 in the adult newt. Finally, the adult frog, which has lost its regeneration capacity, also post-transcriptionally regulates the expression of Hox C6 in its appendages.