合成生物学家以基因作为可互换的零件设计出细胞电路,从而实现新的功能。然而,一个关键的瓶颈影响着这种细胞电路的复杂程度,即很难在互不干扰的情况下将不同的遗传物种整合在一起。MIT的生物工程研究人员实现了这点。

-2012年11月8日《自然》

中文翻译


【题目】最复杂的细胞环路

【译文】遗传程序整合环境传感器,执行信号加工算法并控制表达活性。这些程序是由整合的遗传回路组成,这些遗传回路可单独完成从数字逻辑到活性回路的操作,这些程序被用于多种细胞工程中,包括代谢网络中过程控制的完成和人造组织中立体分化的协调。关键的瓶颈是这些回路是基于发生在细胞狭小容积中的生物化学相互作用的,因此程序的尺寸被限制在很少的回路中。本研究应用部分挖掘和定向进化,在大肠杆菌中建立了一些转录的AND门控。每个AND门控整合了两种启动子输入信号,并控制一个启动子输出信号。这使得这些门控通过上游回路输出启动子作为下游回路输入启动子而被分层。每个门控由一种需要二级伴侣蛋白以激活输出启动子的转录因子所组成。我们在不同细菌的III型分泌途径中鉴定到多种激活因子-伴侣蛋白对。定向进化技术被用于增加动态范围以及回路的正交性。这些门控被连接成不同的排列以形成程序,其中最大的是一个4-输入AND门控,它是由整合4个诱导系统的3个回路所组成,因此需要11个调控蛋白。测量单个门控的性能足以获得完整程序的行为。我们并没有发现归于延迟(故障)的输出信号错误,而这是分层回路中常见的问题。本研究证实了正交逻辑门的成功分层,这是可以使得在单个细胞中构建大的整合回路变为可能的设计策略。

英文原稿


[Title]: Genetic programs constructed from layered logic gates in single cells

[Authors]:Tae Seok Moon,1, 3 Chunbo Lou,1 Alvin Tamsir,2 Brynne C. Stanton1 & Christopher A. Voigt1

[Abstract]:Genetic programs function to integrate environmental sensors, implement signal processing algorithms and control expression dynamics. These programs consist of integrated genetic circuits that individually implement operations ranging from digital logic to dynamic circuits, and they have been used in various cellular engineering applications, including the implementation of process control in metabolic networks and the coordination of spatial differentiation in artificial tissues. A key limitation is that the circuits are based on biochemical interactions occurring in the confined volume of the cell, so the size of programs has been limited to a few circuits. Here we apply part mining and directed evolution to build a set of transcriptional AND gates in Escherichia coli. Each AND gate integrates two promoter inputs and controls one promoter output. This allows the gates to be layered by having the output promoter of an upstream circuit serve as the input promoter for a downstream circuit. Each gate consists of a transcription factor that requires a second chaperone protein to activate the output promoter. Multiple activator–chaperone pairs are identified from type III secretion pathways in different strains of bacteria. Directed evolution is applied to increase the dynamic range and orthogonality of the circuits. These gates are connected in different permutations to form programs, the largest of which is a 4-input AND gate that consists of 3 circuits that integrate 4 inducible systems, thus requiring 11 regulatory proteins. Measuring the performance of individual gates is sufficient to capture the behaviour of the complete program. Errors in the output due to delays (faults), a common problem for layered circuits, are not observed. This work demonstrates the successful layering of orthogonal logic gates, a design strategy that could enable the construction of large, integrated circuits in single cells.

原文地址

http://www.nature.com/nature/journal/v491/n7423/full/nature11516.html

 

本站声明: 生物文库所有文章欢迎转载,所有文章未说明,均属于原创,转载均请注明出处。
本文链接: http://www.bioku.cn/201212/nature-genetic-programs-layered-logic-gates-single-cells-and-gates/
版权所有: 生物文库 - 生物医学、生物技术核心期刊文摘

留言


五 × 5 =


沪ICP备12028140号
点击这里给我发消息   点击这里给我发消息