KCMF1-like suppresses white spot syndrome virus infection by promoting apoptosis in mud crab (Scylla paramamosain).

Potassium channel modulatory factor 1 (KCMF1), an E3 ubiquitin ligase, plays a vital role in renal tubulogenesis, preeclampsia, and tumor development in mammals. Nevertheless, the function of KCMF1 in invertebrates remains to be investigated. Here, we identified KCMF1-like from Scylla paramamosian, encoding 242 amino acids with two zinc finger domains at the N-terminal. Real-time quantitative PCR analysis revealed that KCMF1-like was expressed in all tested tissues, including hemocytes, brain, mid-intestine, subcuticular epidermis, gills, muscle, heart, and stomach, with higher levels in muscle and mid-intestine. KCMF1-like was up-regulated in the hemocytes of mud crabs challenged with white spot syndrome virus (WSSV). RNA interference (RNAi) was performed to investigate the impact of KCMF1-like on the proliferation of WSSV in mud crabs. Knock-down of KCMF1-like resulted in an increase of the WSSV copy number and an impairment of the hemocytes apoptosis rate in vivo. In addition, KCMF1-like could also affect the mitochondrial membrane potential. Collectively, these results revealed that KCMF1-like might play a crucial role in the defense against virus infection in mud crab. This study contributes a novel insight into the role of KCMF1-like in the antiviral immune defense mechanism in crustaceans.