The roles of hox 13 genes in newt limb development and regeneration

PosteriorHoxgenes play crucial roles in limb development and specify regions in the proximal-distal (PD) axis of limbs. However, there is no direct genetic evidence thatHoxgenes are essential for limb regeneration. Moreover, if essential, it is totally unknown whichHoxgenes have the same or distinct functions between development and regeneration. Here, we mutatedhox13using an efficient CRISPR/Cas9 system in newts (Pleurodeles waltl), which have strong regenerative capacities in various tissues. Triple or double mutants ofhox13paralogs lost their digit and metacarpal/metatarsal bones. Limb regeneration progressed but regenerates lacked the same autopod region. These results showed thathox13paralogs have the same functions in limb development and regeneration.