The rational design of complex biological systems through the interconnection of single functional building blocks is hampered by many unpredictability sources; this is mainly due to the tangled context-dependency behavior of those parts once placed into an intrinsically complex living system. Among others, the finite amount of translational resources in prokaryotic cells leads to load effects in heterologous protein expression. As a result, hidden interactions among protein synthesis rates arise, leading to unexpected and counterintuitive behaviors. To face this issue in rational design of synthetic circuits in bacterial cells, CRISPR interference is here evaluated as genetic logic inverters with low translational resource usage, compared with traditional transcriptional regulators. This system has been studied and characterized in several circuit configurations. Each module composing the circuit architecture has been optimized in order to meet the desired specifications, and its reduced metabolic load has been eventually demonstrated via in-vivo assays.

中文翻译：

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CRISPR干扰作为合成电路中的低负担逻辑逆变器：表征和调优

通过单个功能构件的互连来进行复杂生物系统的合理设计受到许多不可预测因素的阻碍。这主要是由于这些部分一旦置于本质上复杂的生活系统中便产生了纠结的上下文相关行为。其中，原核细胞中有限数量的翻译资源会导致异源蛋白表达的负载效应。结果，在蛋白质合成速率之间出现了隐藏的相互作用，从而导致了意想不到和违反直觉的行为。为了在细菌细胞合成电路的合理设计中面对这个问题，与传统的转录调节子相比，CRISPR干扰在这里被认为是翻译资源使用率低的遗传逻辑倒相器。已经对该系统进行了研究并以几种电路配置为特征。组成电路架构的每个模块都经过优化，以满足所需规格，并且最终通过体内试验证明了其降低的代谢负荷。