Zebrafish Rpgr is required for normal retinal development and plays a role in dynein-based retrograde transport process

Mutations in the human RPGR gene cause one of the most common and severe forms of inherited retinal dystrophy, but the function of its protein product remains unclear. We have identified two genes resembling human RPGR (ZFRPGR1, ZFRPGR2) in zebrafish (Danio rerio), both of which are expressed within the nascent and adult eye as well as more widely during development. ZFRPGR2 appears to be functionally orthologous to human RPGR, because it encodes similar protein isoforms (ZFRPGR2ORF15, ZFRPGR2ex1-17) and causes developmental defects similar to other ciliary proteins, affecting gastrulation, tail and head development after morpholino-induced knockdown (translation suppression). These defects are consistent with a ciliary function and were rescued by human RPGR but not by RPGR mutants causing retinal dystrophy.