JAK/STAT signaling regulates the Harmonia axyridis leg regeneration by coordinating cell proliferation

Harmonia axyridis presents remarkable appendage regeneration capacity and can therefore be considered as an emerging regeneration research model. Amino acid sequences of the Janus kinase Hopscotch (Hahop) and the transcription factor STAT (HaStat), the main components of the JAK/STAT signaling pathway, conserved with their homologs in other models. The expression levels of these two genes were continuously up-regulated during the appendage regeneration process. To identify the functions of JAK/STAT signaling, we performed RNAi experiments of Hahop and HaStat in H. axyridis, and found regeneration defects following in Hahop^RNAi and HaStat^RNAi treatments at different regeneration stages. Additionally, we confirmed that regeneration defects caused by the low-level of JAK/STAT activity were due to the inhibition of cell proliferation. The results of the current study suggest that JAK/STAT signaling regulates the entire regeneration process by coordinating cell proliferation of regenerating appendages.