Aim: To express recombinant protein hnRNP I with prokaryotic expression system and assess the presence of autoantibodies against hnRNP I in systemic sclerosis (SSc) as well as other CTD.
Methods: Human hnRNP I gene was amplified by RT-PCR from HeLa cells and cloned into pET-30a vector , then pET-30a-hnRNP I plasmid was transferred into E.coli BL21 (DE3) to express recombinant protein. The sera from patients including SSc, SLE, SS, MCTD, UCTD, RA and controls were detected by ELISA with the purified recombinant hnRNP I protein.
Results: The recombinant protein was highly expressed in E.coli BL21(DE3) and specially reacted with clinically diagnosed SSc patients's serum. The result suggested that the autoantibodies against hnRNP I had higher positive ratio(48.72%) in SSc than other serum of AID and control.
Conclusion: Human hnRNP I protein was successfully expressed in prokaryotic expression system. The purified hnRNP I protein can be used to diagnosis of SSc.