Efficient initiation of mammalian mRNA translation at a CUG codon.
Nucleotide substitutions were made at the initiation codon of an influenza virus NS cDNA clone in a vector carrying the bacteriophage T7 promoter. When capped mRNA transcripts of these constructs were translated in the rabbit reticulocyte lysate, a change in the initiation codon from...AUAAUGG...to...AUACUGG...reduced the in vitro translational efficiency by only 50-60%, and resulted in only a small increase in the yield of short products presumed to be initiated at downstream sites. Synthesis of the full-length product was initiated exclusively at the mutated codon, with negligible use either of in-frame upstream CUG or GUG codons, or of an in-frame downstream GUG codon. We conclude that CUG has the potential to function as an efficient initiation codon in mammalian systems, at least in certain contexts.
Dasso
M C
MC
Department of Biochemistry, University of Cambridge, UK.
Jackson
R J
RJ
D000818:Animals; D001483:Base Sequence; D002474:Cell-Free System; D003062:Codon / Q000235:genetics*; D004279:DNA, Viral / Q000235:genetics; D005814:Genes, Viral; D005822:Genetic Vectors; D009980:Influenza A virus / Q000235:genetics; D008969:Molecular Sequence Data; D010442:Peptide Chain Initiation, Translational; D010957:Plasmids; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics*; D011817:Rabbits; D015183:Restriction Mapping; D012156:Reticulocytes / Q000378:metabolism; D013604:T-Phages / Q000235:genetics
D003062:Codon; D004279:DNA, Viral; D012333:RNA, Messenger