Cloning and expression analysis of shrimp ovarian peritrophin-like gene during early embryonic development in Litopenaeus vannamei

Peritrophin was one type of proteins which was the important structural component of peritrophic membrane (PM) lining the midgut in invertebrate. It was first separated from insect, and played an important role in protecting insects from invasion by microorganisms. Recently, many peritrophin-like genes were identified from tissues not only intestine in crustacean, which implied that the role of peritrophin-like proteins might be diverse. In this study, two cDNA sequences encoding peritrophin-like protein named as LvPT1 and LvPT2 were found and cloned from Litopenaeus vannamei. Their deduced amino acid sequences exhibited high similarity to each other and most other shrimp peritrophins which have been reported. Tissue expression analysis by Real-time PCR revealed that LvPT1 and LvPT2 were mainly expressed in shrimp ovary, similar with shrimp ovarian peritrophins (SOPs). Semi-quantitative RT-PCR was used for analyzing the expression of LvPT2 during the early development of L. vannamei. The results showed that LvPT2 expression was the highest in fertilized eggs, and decreased significantly in developing process. There was no obvious expression of LvPT2 in nauplius hatched out from the hatching membrane. Therefore, we presumed that LvPT1 and LvPT2 might be the same kind of peritrophin to play the similar role with other shrimp SOPs, in participating in the formation and protection of fertilized egg, and protecting shrimp embryo against pathogen infection.