The Research Of Serine Protease Gene Of Chinese Shrimp, Fenneropenaeus Chinensis

The aquaculture of Chinese shrimp has rapidly grown to a major economic activity in our country. However the aquaculture of shrimp has been adversely affected by infectious disease after the 1990's, with losses of total about hundreds of millions of money, and it is still a big problem until now. To solve this problem, one of the important pathways is to raise the antimicrobial ability and innate immunological abilities of shrimp. The immunology mechanism of shrimp must be well understood to give the best way on the diseases treatment.Serine proteases regulate several invertebrate defense responses, including hemolymph coagulation, antimicrobial peptide synthesis, and melanization of pathogen surfaces. These processes require the presence of serine proteases in the hemolymph where they can rapidly activate immune pathways in response to pathogen detection.My studies focus on the serine protease gene which is innate immunity related genes of Chinese shrimp and try to find their functions for giving some information about the immunological mechanism, and for getting new way of control the shrimp infectious disease.1 The serine protease gene was cloned from Chinese shrimp for the first time.A serine protease gene was isolated from hemocytes of Chinese shrimp. It's full-length is 1065bp, which contains a single open reading frame (ORF) of 1020bp encoding a putative serine protease protein of 339 amino acids. The putative serine protease protein was composed of a signal peptide, one clip domain and a Trypsin-like serine protease domain.2 The expression and distribution of serine protease gene in shrimps were analyzed by RT-PCR, Northern Blot and in situ hybridization.The results of RT-PCR and Northern Blot revealed that serine protease gene only expressed in hemocytes and gills, and besides, the results revealed that this gene was down-regulated. These results showed serine protease gene may be related with immune defence. The results of in situ hybridization revealed that serine protease gene only expressed in hemocytes and the positive signal come from hemocytes in gill. 3 Prokaryotic expression of serine protease was studied.Sp which is serine protease gene of Chinese shrimp was cloned into the plasmid pET-30a(+) and the fusion protein was expressed in E.coliBL21(DE3). The fusion protein was purified by affinity chromatograph. These results have laid a good foundation for the functional analysis of serine protease gene of Chinese shrimp.