Background of the antigen
Lupus La protein (Sjogren syndrome type B antigen) (SS-B) (La ribonucleoprotein) (La autoantigen) plays a role in the transcription of RNA polymerase III. It is most probably a transcription termination factor. Binds to the 3' termini of virtually all nascent polymerase III transcripts. It is associated with precursor forms of RNA polymerase III transcripts including tRNA and 4.5S, 5S, 7S, and 7-2 RNAs. The phosphorylation sites are at the C-terminal part of the protein. Sera from patients with systemic lupus erythematosus(SLE) often contain that react with the normal cellular La protein as if this antigen was foreign.
