Institute of Biochemistry, Faculty of Chemistry, Stuttgart University, Stuttgart 70569, Germany.
Nat Commun. 2017 May 24;8:15336. doi: 10.1038/ncomms15336.
Epigenetic systems store information in DNA methylation patterns in a durable but reversible manner, but have not been regularly used in synthetic biology. Here, we designed synthetic epigenetic memory systems using DNA methylation sensitive engineered zinc finger proteins to repress a memory operon comprising the CcrM methyltransferase and a reporter. Triggering by heat, nutrients, ultraviolet irradiation or DNA damaging compounds induces CcrM expression and DNA methylation. In the induced on-state, methylation in the operator of the memory operon prevents zinc finger protein binding leading to positive feedback and permanent activation. Using an mf-Lon protease degradable CcrM variant enables reversible switching. Epigenetic memory systems have numerous potential applications in synthetic biology, including life biosensors, death switches or induction systems for industrial protein production. The large variety of bacterial DNA methyltransferases potentially allows for massive multiplexing of signal storage and logical operations depending on more than one input signal.
表观遗传系统以持久但可逆转的方式在 DNA 甲基化模式中存储信息，但尚未在合成生物学中得到常规应用。在这里，我们使用 DNA 甲基化敏感的工程化锌指蛋白设计了合成表观遗传记忆系统，以抑制包含 CcrM 甲基转移酶和报告基因的记忆操纵子。通过热、营养物、紫外线辐射或 DNA 损伤化合物的触发诱导 CcrM 的表达和 DNA 甲基化。在诱导的开启状态下，记忆操纵子的操纵子中的甲基化阻止锌指蛋白结合，从而导致正反馈和永久激活。使用 mf-Lon 蛋白酶可降解的 CcrM 变体可实现可逆切换。表观遗传记忆系统在合成生物学中有许多潜在的应用，包括生命生物传感器、死亡开关或用于工业蛋白生产的诱导系统。大量的细菌 DNA 甲基转移酶可能允许根据一个以上的输入信号进行大规模的信号存储和逻辑操作的多重化。
