Purification and partial characterization of a nucleolar scleroderma antigen (Mr = 34,000; pI, 8.5) rich in NG,NG-dimethylarginine.
A new scleroderma antigen of Mr = 34,000; pI, 8.5 has been identified. This 34-kDa protein is a nucleolar protein as determined by immunostaining procedures with affinity-purified antibodies. The 34-kDa protein was shown to localize to the fibrillar regions of the nucleolus by immunoelectron microscopy. Antibodies against the 34-kDa protein precipitate U3 RNA-containing particles. The 34-kDa protein has been isolated from Novikoff hepatoma cell nucleoli by ion exchange and reverse-phase column chromatography. The protein contains 4.1 mol % NG,NG-dimethylarginine (DMA) and 22.8 mol % glycine. It is the most highly arginine-methylated protein thus far detected in higher eukaryotes. This nucleolar 34-kDa protein resembles several nucleoplasmic proteins that are associated with heterogeneous nuclear RNA with respect to isoelectric point, Mr, presence of NG,NG-dimethylarginine, and its high glycine content. The amino-terminal sequence of the first 31 residues of the 34-kDa protein is: Met-Lys-Pro-Gly-Phe-Ser-Pro-DMA-Gly-Gly-Gly-Phe-Gly-Gly-DMA-Gly-Gly- Phe-Gly-Asp-DMA-Gly-Gly-DMA-Gly-Gly-Gly-DMA-Gly-Gly-DMA. In the first 31 residues, there are 16 glycine, 6 DMA, and 3 phenylalanine residues. This is a novel demonstration of clusters of glycine and DMA in a protein.
M A
MA
Lischwe
R L
RL
Ochs
R
R
Reddy
R G
RG
Cook
L C
LC
Yeoman
E M
EM
Tan
M
M
Reichlin
H
H
Busch
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000941:Antigens / Q000032:analysis*; D001120:Arginine / Q000031:analogs & derivatives* / Q000032:analysis; D001323:Autoantibodies / Q000276:immunology; D002466:Cell Nucleolus / Q000032:analysis / Q000276:immunology*; D005455:Fluorescent Antibody Technique; D006651:Histocytochemistry; D006801:Humans; D007158:Immunologic Techniques; D007163:Immunosorbent Techniques; D008114:Liver Neoplasms, Experimental / Q000032:analysis; D008854:Microscopy, Electron; D008970:Molecular Weight; D010804:Physarum / Q000276:immunology; D011506:Proteins / Q000276:immunology*; D012313:RNA / Q000276:immunology; D012595:Scleroderma, Systemic / Q000276:immunology*
D000596:Amino Acids; D000941:Antigens; D001323:Autoantibodies; D011506:Proteins; D012313:RNA; C018524:N,N-dimethylarginine; D001120:Arginine