Genetically Modified Organism Research Center, National Institute of Agrobiological Sciences , Tsukuba, Ibaraki , Japan.
PeerJ. 2015 Apr 28;3:e904. doi: 10.7717/peerj.904. eCollection 2015.
Translation of target gene transcripts in Escherichia coli harboring UAG amber stop codons can be switched on by the amber-codon-specific incorporation of an exogenously supplied unnatural amino acid, 3-iodo-L-tyrosine. Here, we report that this translational switch can control the translational efficiency at any intermediate magnitude by adjustment of the 3-iodo-L-tyrosine concentration in the medium, as a tunable translational controller. The translational efficiency of a target gene reached maximum levels with 10(-5) M 3-iodo-L-tyrosine, and intermediate levels were observed with suboptimal concentrations (approximately spanning a 2-log10 concentration range, 10(-7)-10(-5) M). Such intermediate-level expression was also confirmed in individual bacteria.
在携带 UAG 琥珀终止密码子的大肠杆菌中，目标基因转录本的翻译可以通过外源性供应的非天然氨基酸 3-碘-L-酪氨酸的琥珀密码子特异性掺入来开启。在这里，我们报告说，通过在培养基中调整 3-碘-L-酪氨酸的浓度，可以将这种翻译开关以可调节的翻译控制器的形式将翻译效率控制在任何中间幅度。目标基因的翻译效率在 10(-5) M 3-碘-L-酪氨酸时达到最大水平，而在亚最佳浓度（大约跨越 2-log10 浓度范围，10(-7)-10(-5) M）时观察到中间水平。在单个细菌中也证实了这种中间水平的表达。
