MOLECULAR-CLONING OF A NOVEL 97-KD GOLGI-COMPLEX AUTOANTIGEN ASSOCIATED WITH SJOGRENS-SYNDROME

Objective, To identify a Golgi complex autoantigen bound by Sjogren's syndrome (SS) autoantibodies. Methods, Serum from a patient with secon dary SS and anti-Golgi antibodies was used as a probe to isolate a com plementary DNA (cDNA) insert from a HeLa cDNA library. Results, A 3.7- kb cDNA encoding a 56-kd recombinant protein was immunoprecipitated by the human anti-Golgi serum and immune rabbit serum. Western blot anal ysis showed that the immune rabbit sera recognized a protein of 97 kd (golgin-97), suggesting that the isolated clone contained a partial cD NA, The 5' upstream sequence was obtained by rapid amplification of th e cDNA ends, The complete cDNA contained 4,860 basepairs, encoding a p rotein with a calculated M-r of 88 kd. Antibodies to golgin-97 were fo und in 12 (20%) of 60 sera known to have anti-Golgi autoantibodies, an d the majority of these sera (8 of 12, or 75%) were from patients who had secondary SS, Conclusion, Golgin-97 is a unique Golgi complex anti gen that appears to be a target of SS autoantibodies.