Is TALPID3 a Wnt/PCP pathway gene?

TALPID3 (KIAA0586) is an essential gene for vertebrate development. TALPID3 was first mapped in the recessive, embryonic lethal, polydactylous talpid3 chicken breed at The Roslin Institute, Edinburgh (Davey et al. 2006). The TALPID3 protein localises to the centrosome in human, chicken mouse and zebrafish cells and mutations in these species cause a loss of cilia formation, a loss Hedgehog pathway regulation and embryonic lethality. In the chicken there are several phenotypes which cannot be explained by abnormal Hedgehog signalling, such as polycystic kidneys and abnormal feather patterning. Since centrosomes are mislocalised in the cell we suggest that TALPID3 might act in the Wnt/PCP pathway to direct centrosome migration and docking before ciliogenesis. In the talpid3 mouse left/right axis patterning, which is controlled by Hedgehog signalling, is disrupted but heart looping and other left/right axis patterning is normal in the talpid3 chicken. We have found that cilia, Hedgehog signalling and localisation of Wnt/PCP pathway components are normal in stage 4-7HH chicken talpid3 embryos. TALPID3 is a maternal effect gene in zebrafish and Xenopus, and we have therefore explored the novel possibility of maternal effect in chickens. Understanding maternal effect in chicken development has implication for interpreting future transgenic knock-out phenotypes in chickens which may be circumvented by primordial germ cell replacement technology.