Identification of the Ro and La antigens in the endoribonuclease VII--ribonucleoprotein complex.
45 S RNP (ribonucleoprotein) particles from calf thymus or L5178y mouse lymphoma cells contain the poly(A)-modulated and oligo(U)-binding endoribonuclease VII [Bachmann, Zahn & Müller (1983) J. Biol. Chem. 258, 7033-7040]. From these particles a 4.5 S RNA was isolated that possesses an oligo(U) sequence. By using monospecific and non-cross-reacting antibodies directed against the La or Ro antigen, both proteins were identified in the endoribonuclease VII-RNP complex after phosphorylation in vitro. In a second approach, endoribonuclease VII activity was identified in immunoaffinity-purified Ro RNPs after preparative isoelectric focusing. Therefore we conclude that the 4.5 S RNA belongs to the Ro RNAs. The results indicate a possible function of endoribonuclease VII in activating stored mRNAs.
D000818:Animals; D000906:Antibodies / Q000276:immunology; D001324:Autoantigens / Q000032:analysis*; D011232:Chemical Precipitation; D004722:Endoribonucleases / Q000276:immunology*; D046911:Macromolecular Substances; D051379:Mice; D012313:RNA / Q000032:analysis; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins / Q000032:analysis* / Q000276:immunology; D000097585:SS-B Antigen; D000099207:SS-A Antigen
D000906:Antibodies; D001324:Autoantigens; D004722:Endoribonucleases; D046911:Macromolecular Substances; D012313:RNA; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins; D000097585:SS-B Antigen; D000099207:SS-A Antigen; C116006:RO60 protein, human; C038251:endoribonuclease VII