碩士 / 國立臺灣大學 / 動物學研究研究所 / 94 / Abstract
Clip domain serine protease homologs (c-SPHs) are involved in various innate immune functions in arthropods such as antimicrobial activity, cell adhesion, pattern recognition, opsonization, and regulation of the prophenoloxidase system. In the present study, we cloned a c-SPH cDNA from tiger shrimp (Penaeus monodon) hemocytes. It is 1337 bp in length with a coding region of 1068 bp consisting a protein of 355 amino acid residues. The deduced protein includes one clip domain and one catalytically inactive serine protease-like (SP-like) domain. Its molecular weight is estimated to be 38 kDa with an isoelectric point of 7.9. The predicted cutting site of the signal peptide is located between Gly21 and Gln22. We aligned 15 single clip domain SPH protein sequences from 12 arthropod species; the similarity of these clip domains is low and that of SP-like domains is from 34%-46%. The conserved regions are located near the amino acid residues which served as substrate interaction sites in catalytically active serine protease. Phylogenetically, the tiger shrimp c-SPH is most similar to a low molecular mass masquerade-like protein of crayfish, also a member of Decapoda, but less similar to c-SPHs in Chelicerata and Insecta. Nested reverse transcription polymerase chain reaction (RT-PCR) revealed that c-SPH mRNA is expressed most in tissues with the highest hemocyte abundance. Antimicrobial, opsonization and proPO regulation of the molecule were not detected. The expression of c-SPH mRNA in hemocytes was up-regulated at the 12 day post β-glucan immersion and down-regulated at 0.5 hr post heat-inactivated Vibrio immersion. Recombinant c-SPH could significantly enhance hemocyte adhesion. The results suggest that the shrimp c-SPH protein plays a role in innate immunity.
| Identifer | oai:union.ndltd.org:TW/094NTU05312008 |
| Date | January 2006 |
| Creators | Chun-Yu Lin, 林均郁 |
| Contributors | 宋延齡 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 52 |
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