Detection of planarian Antennapedia-like homeobox genes expressed during regeneration.

Using the polymerase chain reaction with degenerate oligo primers we identified six new Antennapedia-like homeobox sequences expressed in a regenerating planarian. cDNA fragments containing the entire homeobox sequences for four of these genes were obtained. Two of them, Dutarh-3 and Dutarh-4, belong to the classical Antennapedia type and display extensive identity with Antennapedia- and Deformed-type homeodomains respectively. The third homeodomain, Dutarh-1, exhibits some similarity to the Hox1.5-, AbdB- and Dfd-type homeodomains and a fourth gene, Dutarh-6, is very similar to Mox2 in the mouse. Our results suggest that, in spite of their simple body plan, planarians contain a number of Antennapedia-like homeobox genes, probably enough to fill a cluster such as found in higher animals.