title: La antigen recognizes and binds to the 3'-oligouridylate tail of a small RNA.
abstract: The La antigen is a cellular protein which interacts with many RNA species that are products of RNA polymerase III, including the adenovirus virus-associated (VA) RNAs. We demonstrate that the efficiency of antigen binding in vitro is determined by the number of U residues at the RNA 3' terminus. Forms of VA RNAI with more than two terminal U residues are fully bound, forms with two U residues are partially bound, and forms with fewer than two U residues are not bound at all. The antigen can be covalently linked to VA RNA by UV irradiation, and the site of cross-linking is shown to contain the 3' terminus of the RNA. We conclude that the antigen recognizes the U-rich 3' tail of VA RNA, and presumably that of other polymerase III products, and that it binds at or close to this site.
mesh_terms: D000227:Adenine Nucleotides / Q000378:metabolism*; D000260:Adenoviruses, Human / Q000235:genetics; D000941:Antigens / Q000378:metabolism*; D001324:Autoantigens; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008970:Molecular Weight; D009841:Oligonucleotides / Q000378:metabolism*; D009843:Oligoribonucleotides / Q000378:metabolism*; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D000097585:SS-B Antigen
chemical_list: D000227:Adenine Nucleotides; D000941:Antigens; D001324:Autoantigens; D009841:Oligonucleotides; D009843:Oligoribonucleotides; D012367:RNA, Viral; D012261:Ribonucleoproteins; D014157:Transcription Factors; D000097585:SS-B Antigen; C036867:3'-5'-oligoadenylate