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Autoantibodies to ribonucleoprotein particles containing U2 small nuclear RNA.
Author(s) -
Habets W.,
Hoet M.,
Bringmann P.,
Lührmann R.,
Venrooij W.
Publication year - 1985
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1985.tb03815.x
Subject(s) - ribonucleoprotein , snrnp , autoantibody , rna , biology , small nuclear ribonucleoprotein , microbiology and biotechnology , antigen , genetics , antibody , gene
Autoantibodies exclusively precipitating U1 and U2 small nuclear ribonucleoprotein (snRNP) particles [anti‐(U1,U2)RNP] were detected in sera from four patients with autoimmune disorders. When tested by immunoblotting, these sera recognized up to four different protein antigens in purified mixtures of U1‐U6 RNP particles. With purified antibody fractions eluted from individual antigen bands on nitrocellulose blots, each anti‐(U1,U2)RNP serum precipitated U2 RNP by virtue of the recognition of a U2 RNP‐specific B″ antigen (mol. wt. 28 500). Antibodies to the U2 RNP‐specific A' protein (mol. wt. 31 000) were found in only one serum. The B″ antigen differs slightly in mol. wt. from the U1‐U6 RNA‐associated B/B' antigens and can be separated from this doublet by two‐dimensional gel electrophoresis, due to its more acidic pI. In immunoprecipitation assays, the purified anti‐B″ antibody specificity also reacts with U1 RNPs which is due to cross‐reactivity of the antibody with the U1 RNA‐specific A protein, as demonstrated by immunoblotting using proteins from isolated U1 RNPs as antigenic material. Thus the A antigen not only bears unique antigenic sites for anti‐A antibodies contained in anti‐(U1)RNP sera, it also shares epitopes with the U2 RNP‐specific B″ antigen.