Translation regulation of integrons gene cassette expression by the attC sites
Translation regulation of integrons gene cassette expression by the attC sites
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DOI：
10.1111/j.1365-2958.2009.06736.x
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发表时间：
2009-06-01
影响因子：
3.6
通讯作者：
Bercot, Beatrice
中科院分区：
文献类型：
--
作者：
Jacquier, Herve;Zaoui, Caroline;Bercot, Beatrice
整合子是能够携带、捕获和改组基因盒中的基因的遗传元件. attC重组位点在单链时采用稳定的二级结构，这是其重组所必需的。在这项研究中，我们评估了attC位点的结构对1类整合子中3'基因表达的影响。这通过用跨越宽范围大小和二级结构的各种突变attC位点取代bla（IMP-8）基因盒的attC，并测量3' aac（6'）-Ib（7）基因的整合子依赖性翻译来分析。在所得构建体中，5 ′-attC位点差异性地影响aac（6 ′）-Ib（7）基因的表达。与从它们作为Rho非依赖性转录终止子的作用所预期的相反，aac（6 '）-Ib（7）基因的转录不受各种attC位点的影响。天然位点的突变揭示了转录物中attC位点的潜在茎环结构的不稳定可以增强3'基因的表达。特别地，翻译的开放阅读框的存在显示增加3'基因的翻译。这些发现可能被解释为茎环结构阻碍核糖体进展的能力。
P>Integron are genetic elements able to carry, capture and shuffle the genes embedded in gene cassettes. The attC recombination sites adopt a stable secondary structure when single-stranded that is necessary for their recombination. In this study, we evaluated the impact of the structure of the attC site on expression of the 3' gene in class 1 integrons. This was analysed by substituting the attC of the bla(IMP-8) gene cassette with various mutated attC sites spanning a wide range of sizes and secondary structures, and measuring the integron-dependent translation of the 3' aac(6')-Ib(7) gene. In the resulting constructs, the 5'-attC site differentially affected the expression of the aac(6')-Ib(7) gene. Contrary to what was expected from their proposed role as Rho-independent transcription terminators, the transcription of the aac(6')-Ib(7) gene was not affected by the various attC sites. Mutations of natural sites revealed that destabilization of the potential stem-loop structure of the attC site in the transcript could enhance the expression of the 3' gene. In particular, the presence of a translated open reading frame was shown to increase translation of the 3' gene. These findings might be explained by the capacity of the stem-loop structures to impede ribosome progression.