Dasso M C, Jackson R J
Department of Biochemistry, University of Cambridge, UK.
Nucleic Acids Res. 1989 Aug 25;17(16):6485-97. doi: 10.1093/nar/17.16.6485.
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.
在携带噬菌体T7启动子的载体中，对流感病毒NS cDNA克隆的起始密码子进行了核苷酸替换。当这些构建体的加帽mRNA转录本在兔网织红细胞裂解物中进行翻译时，起始密码子从...AUAAUGG...变为...AUACUGG...，仅使体外翻译效率降低了50 - 60%，并且仅导致推测在下游位点起始的短产物产量略有增加。全长产物的合成仅在突变密码子处起始，对框内上游的CUG或GUG密码子以及框内下游的GUG密码子的使用可忽略不计。我们得出结论，至少在某些情况下，CUG在哺乳动物系统中具有作为有效起始密码子发挥作用的潜力。
