Prokaryotic Expression and Immunoreactivity Analysis on Profilin of Toxoplasma gondii

OBJECTIVE: To clone and express the profilin (PRF) gene of Toxoplasma gondii, and analyze the immunoreactivity. METHODS: Total RNA was extracted from tachyzoites of T. gondii RH strain. The coding region of TgPRF was amplified with a pair of specific primers. PCR product was digested with double restriction enzyme and ligated into pET30a(+) vector. The recombinant pET30a(+)-TgPRF plasmid was transformed into E. coli DH5α with positive clones confirmed by the double restriction enzyme digestion, PCR and sequencing. The correct plasmid was transformed into E. coli BL21 and induced by IPTG. The expressed proteins were purified with Ni-NTA affinity chromatography and analyzed by SDS-PAGE. Western blotting with rabbit anti-T. gondii serum was used to analyze its antigenicity. RESULTS: The product of RT-PCR was with 492 bp. pET30a-TgPRF was confirmed by the double restriction enzyme digestion, PCR and sequencing. SDS-PAGE analysis showed that the expressed product was a soluble protein with a relative molecular weight of 35,000. Western blotting assay revealed that rTgPRF was recognized by rabbit anti-T. gondii serum. CONCLUSION: TgPRF gene has been expressed in prokaryotic expression system and shows immunoreactivity.