title: Regulation of in vitro translation by double-stranded RNA in mammalian cell mRNA preparations.
abstract: Polyadenylated mRNA has been purified from a variety of human and mouse cell sources. These preparations are actively translated in the wheat germ cell-free system but have only poor ability to stimulate the nuclease-treated reticulocyte lysate. The translation of endogenous and exogenous globin mRNA is strongly inhibited by the poly(A)+ RNA preparations in reticulocyte lysates. Both polysomal and non-polysomal RNA have similar effects but poly(A)+ RNA is almost 2000-fold more inhibitory than poly(A)-RNA on a weight basis. The inhibition is abolished in the presence a high concentration of poly(I).poly(C). Analysis of endogenous eIF-2 in the lysate reveals that the subunit becomes extensively phosphorylated in the presence of the inhibitory poly(A)+ RNA. Prolonged incubation of lysate with poly(A)+ RNA also causes some nucleolytic degradation of polysomal globin mRNA. These characteristics suggest that some eukaryotic cell mRNAs contain regions of double-stranded structure which are sufficiently extensive to activate translational control mechanisms in the reticulocyte lysate.
mesh_terms: D000818:Animals; D002474:Cell-Free System; D003864:Depression, Chemical; D004789:Enzyme Activation / Q000187:drug effects; D015852:Eukaryotic Initiation Factor-2; D005786:Gene Expression Regulation / Q000187:drug effects*; D005914:Globins / Q000235:genetics; D006801:Humans; D051379:Mice; D009690:Nucleic Acid Conformation; D010448:Peptide Initiation Factors / Q000378:metabolism; D011061:Poly A / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology*; D011070:Poly I-C / Q000494:pharmacology; D014176:Protein Biosynthesis / Q000187:drug effects*; D011506:Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology*; D012334:RNA, Neoplasm / Q000378:metabolism; D011817:Rabbits; D012156:Reticulocytes; D014908:Triticum; D014407:Tumor Cells, Cultured
chemical_list: D015852:Eukaryotic Initiation Factor-2; D010448:Peptide Initiation Factors; D011506:Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D011061:Poly A; D005914:Globins; D011070:Poly I-C