Differential effects of two interferon-induced translational inhibitors on initiation of protein synthesis.
At least two different mechanisms for the inhibition of mRNA translation operate in extracts of interferon-treated L cells. One is mediated by an interferon-induced protein kinase which, when activated by double-stranded RNA and ATP, phosphorylates the small subunit of initiation factor eIF-2. Addition of the purified interferon-induced protein kinase to L cell extracts, strongly reduces the amount of methionyl-tRNA bound to 40-S ribosomal subunits. The second translational inhibition is due to the synthesis of (2'-5')oligo(adenylate) by interferon-induced enzyme E. The oligonucleotide in turn activates a ribonuclease F constitutively present in L cells. Addition of the purified nuclease with its oligonucleotide activator to L cell extracts produces a strong decrease in polyribosome formation and an accumulation of initiation complex. These experiments differentiate the effects of the two interferon-induced inhibitors on mRNA translation.
D000818:Animals; D007372:Interferons / Q000494:pharmacology*; D007739:L Cells / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D010442:Peptide Chain Initiation, Translational / Q000187:drug effects*; D010448:Peptide Initiation Factors / Q000378:metabolism; D010766:Phosphorylation; D014176:Protein Biosynthesis / Q000187:drug effects*; D011494:Protein Kinases / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012260:Ribonucleases / Q000378:metabolism; D013698:Templates, Genetic
D010448:Peptide Initiation Factors; D012333:RNA, Messenger; D007372:Interferons; D011494:Protein Kinases; D012260:Ribonucleases