title: Identification of a 90-kDa polypeptide which associates with adenovirus VA RNAI and is phosphorylated by the double-stranded RNA-dependent protein kinase.
abstract: Interferon treatment of mammalian cells induces a double-stranded (ds) RNA-dependent protein kinase known as DAI. When activated, DAI phosphorylates the alpha-subunit of eukaryotic initiation factor eIF-2, impairing its ability to be recycled and leading to the inhibition of protein synthesis. We have identified a novel DAI substrate in the ribosomal salt wash of rabbit reticulocyte lysates. This substrate is a 90-kDa polypeptide which has been purified to apparent homogeneity. It can be cross-linked by ultraviolet irradiation to adenovirus VA RNAI, a small RNA polymerase III transcript RNA which acts as an inhibitor of DAI. As assayed by a nitrocellulose filter binding assay, the 90-kDa polypeptide is also able to associate with authentic double-stranded RNA, but not single-stranded RNA, made in vitro. Thus, this newly identified substrate of DAI appears to have affinity for dsRNA structures and may be involved in dsRNA-regulated processes in the reticulocyte. Polyclonal and monoclonal antibodies directed against the 90-kDa polypeptide co-precipitate DAI, suggesting that these two proteins may exist as a complex.
authors.affiliation: Cold Spring Harbor Laboratory, New York 11724.
authors.forename: A P
authors.initials: AP
authors.lastname: Rice
authors.forename: M
authors.initials: M
authors.lastname: Kostura
authors.forename: M B
authors.initials: MB
authors.lastname: Mathews
mesh_terms: D000260:Adenoviruses, Human / Q000378:metabolism*; D000818:Animals; D000906:Antibodies; D000936:Antigen-Antibody Complex / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D008970:Molecular Weight; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D012367:RNA, Viral / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D011817:Rabbits; D012156:Reticulocytes / Q000378:metabolism; D014764:Viral Proteins / Q000302:isolation & purification / Q000378:metabolism*; D019892:eIF-2 Kinase
chemical_list: D000906:Antibodies; D000936:Antigen-Antibody Complex; D012367:RNA, Viral; D014764:Viral Proteins; C052835:adenovirus associated RNA; D011494:Protein Kinases; D019892:eIF-2 Kinase