title: Translational readthrough-promoting drugs   enhance pseudoknot-mediated suppression of the   stop codon at the Moloney murine leukemia virus   gag–pol junction.
abstract: Translational readthrough-promoting drugs enhance the incorporation of amino acids at stop codons and can thus bypass premature termination during protein synthesis. The polymerase (Pol) proteins of Moloney murine leukemia virus (MoMLV) are synthesized as a large Gag–Pol fusion protein, formed by the readthrough of a stop codon at the end of the gag ORF. The downstream pol ORF lacks its own start codon, and Pol protein synthesis is wholly dependent on translation of the upstream gag gene and the readthrough event for expression. Here, we explored the effects of readthrough-promoting drugs – aminoglycoside antibiotics and the small molecule ataluren – on the efficiency of readthrough of the stop codon in the context of the MoMLV genome. We showed that these compounds increased readthrough of the stop codon at the MoMLV gag–pol junction in vivo above the already high basal level and that the resulting elevated gag–pol readthrough had deleterious effects on virus replication. We also showed that readthrough efficiency could be driven to even higher levels in vitro, and that the combination of the small molecules and the RNA structure at the MoMLV stop codon could achieve extremely high readthrough efficiencies.
authors.affiliation: Department of Biological Sciences, Columbia University Medical Center, New York, NY 10032, USA.
authors.forename: Lisa
authors.initials: L
authors.lastname: Green
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, NY 10032, USA.|Howard Hughes Medical Institute, Columbia University Medical Center, New York, NY 10032, USA.|Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032, USA.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Goff
mesh_terms: D000617:Aminoglycosides / Q000009:adverse effects / Q000494:pharmacology*; D000818:Animals; D002460:Cell Line; D018388:Codon, Terminator; D015685:Fusion Proteins, gag-pol / Q000235:genetics* / Q000378:metabolism; D015967:Gene Expression Regulation, Viral / Q000187:drug effects; D006801:Humans; D051379:Mice; D008979:Moloney murine leukemia virus / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D010069:Oxadiazoles / Q000009:adverse effects / Q000494:pharmacology*; D014176:Protein Biosynthesis / Q000187:drug effects*
chemical_list: D000617:Aminoglycosides; D018388:Codon, Terminator; D015685:Fusion Proteins, gag-pol; D010069:Oxadiazoles; C515878:ataluren