Does analysis of the Wnt gene repertoire in an onychophoran provide new insights into the evolution of segmentation?
Many onychophoran Wnt genes are expressed in segment polarity gene-like patterns, suggesting a general role for these ligands during segment regionalization, as has been described in arthropods. During early stages of development, Wnt2, Wnt4, and Wnt5 are expressed in broad multiple segment-wide domains that are reminiscent of arthropod gap and Hox gene expression patterns, which suggests an early instructive role for Wnt genes during E. kanangrensis segmentation.
The results confirm the phosphaturic effect of MEPE and indicate that much, if not all, of this effect is a result of reduced reabsorption of phosphate in the proximal convoluted tubule. This is consistent with the recent finding of MEPE-induced reductions in apically located NaPT2a in the proximal tubule.