[Identification of glycosylphosphatidylinositol-anchored protein from Schistosoma japonicum].

OBJECTIVE

To identify glycosylphosphatidylinositol (GPI) anchored protein of Schistosoma japonicum.

METHODS

Based on the gene sequence of Schistosoma mansoni GPI anchored protein Sm200 (GenBank Assess No: XM_002569560.1), bioinformatics analysis was performed to find out its homologous gene sequence in S. japonicum, then a selected partial coding sequence (SjGPIs, about 933 bp) from the homologous gene sequence were amplified, and cloned into PET-28a(+) vector. The recombinant plasmid pET-28a(+)SjGPIs were transformed into E. coli Top10 cells and induced with IPTG for protein expression. The recombinant protein SjGPIs was purified with Ni-NTA resin, and the purified recombinant SjGPIs protein was used as antigen to prepare antiserum in New Zealand rabbit. The antiserum was used to detect S. japonicum GPI-anchored protein. To identify a GPI-anchored protein, the detected protein were identified by phosphatidylinositol-specific phospholipase C (PI-PLC) digestion. White blood cells from S. japonicum-infected mice was examined whether they endocytosed GPI-anchored proteins by Western blotting.

RESULTS

The homologous gene sequence of S. mansoni GPI Sm200 gene was found in S. japonicum genome. A 3 495 bp coding sequence was obtained, containing the complete C-terminal sequence. The selected gene sequence (SjGPIs) were amplified and the recombinant plasmid pET-28a(+)-SjGPIs was established. According to the analysis of C-terminal sequence, Western blotting and enzyme digestion of PI-PLC, a GPI-anchored protein was present in S. japonicum tegument (about 1M(r)200000), named SjGPI200. The protein was detected in white blood cells of infected mice.

CONCLUSION

SjGPI200 protein exists in S. japonicum, and anchored to parasite tegument via GPI.