Rare scleroderma autoantibodies to the U11 small nuclear ribonucleoprotein and to the trimethylguanosine cap of U small nuclear RNAs.
We have identified a scleroderma serum (Ru) with a previously undescribed specificity to protein components of the U11 small nuclear ribonucleoprotein particle (snRNP), a low-abundance member of the Sm class of U RNPs. The U11 RNP can be specifically immunoprecipitated from sonicated HeLa cells with Ru serum. In nuclear extracts, a fraction of the U11 particle is found complexed to the U12 RNP, an even lower abundance Sm snRNP. In glycerol gradient fractions, Ru serum identifies a 65-kDa protein that cosediments with the U11-U12 complex and is shifted upon targeted degradation of the U12 RNA. The 65-kDa protein therefore appears to be a component of the U11-U12 snRNP complex, whereas another Ru-reactive (140 kDa) protein may be associated with the free U11 RNP. The Ru serum also contains autoantibodies directed against the trimethylguanosine cap of U RNAs. This rare specificity has been described previously in only three other scleroderma patients.
Gilliam
A C
AC
Department of Dermatology, Yale University School of Medicine, New Haven, CT.
Steitz
J A
JA
D000328:Adult; D000974:Antibodies, Antinuclear / Q000276:immunology*; D000918:Antibody Specificity; D005260:Female; D006151:Guanosine / Q000031:analogs & derivatives / Q000276:immunology; D006801:Humans; D012315:RNA Caps / Q000276:immunology; D012342:RNA, Small Nuclear / Q000276:immunology*; D017411:Ribonucleoproteins, Small Nuclear / Q000737:chemistry / Q000276:immunology*; D012595:Scleroderma, Systemic / Q000276:immunology*; D017423:Sequence Analysis, RNA
D000974:Antibodies, Antinuclear; D012315:RNA Caps; D012342:RNA, Small Nuclear; D017411:Ribonucleoproteins, Small Nuclear; D006151:Guanosine; C017778:N(2),N(2),7-trimethylguanosine