Bonekamp F, Andersen H D, Christensen T, Jensen K F
Nucleic Acids Res. 1985 Jun 11;13(11):4113-23. doi: 10.1093/nar/13.11.4113.
This communication describes an assay for the relative translation efficiency of individual codons which makes use of the pyrE attenuator to probe the coupling between transcription and translation at the end of an artificial leader peptide. By cloning of short synthetic DNA fragments the codons to be tested were placed in the middle of the leader peptide and the downstream transcription of a pyrE"lacZ gene was monitored by measuring beta-galactosidase activity. The substitution, one by one, of three AGG codons for arginine with three CGT codons for the same amino acid residue was found to cause a two fold increase per codon of transcription over the pyrE attenuator, such that an eight fold higher frequency of pyrE expression was seen when all three AGG codons were replaced by CGT codons. No such effect of codon composition was observed, when the cells were grown with a low UTP pool which causes a reduction of the mRNA chain growth rate.
本通讯描述了一种用于检测单个密码子相对翻译效率的测定方法,该方法利用pyrE衰减子来探测人工前导肽末端转录与翻译之间的偶联。通过克隆短的合成DNA片段,将待测试的密码子置于前导肽中间,并通过测量β-半乳糖苷酶活性来监测pyrE“lacZ基因的下游转录。发现用三个编码相同氨基酸残基的CGT密码子逐个替换三个编码精氨酸的AGG密码子,会导致每个密码子通过pyrE衰减子的转录增加两倍,以至于当所有三个AGG密码子都被CGT密码子替换时,pyrE表达频率高出八倍。当细胞在低UTP库中生长导致mRNA链生长速率降低时,未观察到密码子组成的这种影响。