[Cloning and prokaryotic expression of recombinant Jo-1 antigen and identification of its antigen specificity].

AIM: To obtain highly purified Jo-1 autoantigens.

METHODS

The full length of DNA sequence coding for Jo-1 (histidyl-tRNA synthetase) was obtained from human placenta by RT-PCR and then it was inserted into pTYB11 or pMAL-c to construct the expression vectors pTYB11-Jo-1 and pMAL-c-Jo-1. The recombinant plasmids were transformed into ER2566 and BL21 of E.coli, respectively.

RESULTS

The fusion Jo-1 antigens were expressed, Western blot analysis demonstrated they responded specifically to anti-Jo-1 antibody from the patients with autoimmune disease polymyositis and dermatomyositis, but did not respond to normal sera and 188 sera containing anti-RNP, Sm, Ro/La or RNP/Ro antibodies from rheumatosis patients.

CONCLUSION

The expressed protein of pMAL-c-Jo-1 is soluble, which accounts for more then 50% of total proteins of cells and can be purified by affinity chromatography. The purified proteins can be used as reagents for determining the anti Jo-1 antibody in the serum of patients.