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.
Department of Biochemistry, University of Cambridge, UK.
M C
MC
Dasso
R J
RJ
Jackson
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