Expression of teneurin-m/odd Oz during segmentation in the beetle Tribolium castaneum

The pair-rule gene teneurin-m/odd Oz (ten-m/odz) is required for the patterning of alternate segment boundaries in the early Drosophila embryo. Mutant phenotypes of ten-m/odz display a typical pair-rule phenotype in which odd-numbered segments are eliminated. Consistent with its pair-rule function, Ten-m/Odz protein is expressed in a seven-stripe pattern before the onset of gastrulation. While expression of ten-m/odz orthologues have been characterized in several vertebrate species, their expression patterns in non-Drosophila arthropods during embryonic segmentation have yet to be reported. Here, we have identified a Tribolium orthologue of ten-m/odz (Tc-ten-m/odz) and analyzed its expression patterns during embryonic segmentation. Tc-ten-m/odz expression was observed in a region of the growth zone, which appeared to be a potential mesodermal region, during germband elongation. Later, segmental expression appeared in the trunk after segments had already formed. In contrast to Drosophila, apparently Tc-ten-m/odz was neither expressed in the ectoderm of the growth zone where segmentation occurs, nor the ectoderm of trunk regions where segmentation is maintained. Our findings suggest that Tc-ten-m/odz may not function as a pair rule gene in Tribolium segmentation.