A Clip Domain Serine Protease Involved in Egg Production in Nilaparvata lugens: Expression Patterns and RNA Interference

Clip domain serine proteases play vital roles in various innate immune functions and in embryonic development. Nilaparvata lugens proclotting enzymes (NlPCEs) belong to this protease family. NlPCE1 was reported to be involved in innate immunity, whereas the role of other NlPCEs is unclear. In the present study, N. lugens proclotting enzyme-3 (NlPCE3) was cloned and characterized. NlPCE3 contains a signal peptide, a clip domain, and a trypsin-like serine protease domain. NlPCE3 was expressed in all tissues examined (gut, fat body, and ovary), and at all developmental stages. Immunofluorescence staining showed that NlPCE3 was mainly expressed in the cytoplasm and cytomembrane of follicular cells. Double stranded NlPCE3 RNA interference clearly inhibited the expression of NlPCE3, resulting in abnormal egg formation and obstruction of ovulation. These results indicate that NlPCE3 plays an important role in egg production in N. lugens.