耐辐射奇球菌全局调控蛋白IrrE作为抗逆元件的机制及应用

Mechanism and applications of the global regulator IrrE from Deinococcus radiodurans using as tolerance elements

细胞对不良环境的耐受性属于复杂表型,往往由多个基因控制,且有着严格的调控机制,难以通过操作单个基因来提升耐受性。利用全局转录调控因子来提升细胞对不良环境耐受性成为一种重要的策略。耐辐射奇球菌(Deinococcus radiodurans)的全局转录调控蛋白IrrE(或PprI),其分子大小为3.5×10^(4),对重组修复系统具有去阻遏和激活作用,与细胞的耐辐射性能直接相关。此后,在多项研究中发现,IrrE可以作为极端应激反应的全局调控因子,提高了外源宿主的应激能力。irrE在大肠杆菌、酿酒酵母、运动单胞菌等菌株中的异源表达可以导致宿主的转录组发生显著变化,激发宿主菌对抗抑制物、高渗透压、高温、溶剂等不良环境胁迫。IrrE及其突变体作为抗逆元件,已经在燃料乙醇、有机酸、生物聚合物、微生物燃料电池以及生物修复等领域进行了应用研究,取得了较好的效果。

The tolerance of cells to stresses was a complex phenotype, which was often controlled by multiple genes and had a strict regulatory mechanism. It was always difficult to enhance the stress tolerance by manipulating a single gene. Global regulators had been shown to be effective approaches for enhancing stress tolerance. The global regulator IrrE(or PprI) of Deinococcus radiodurans, a protein of 3.5×10^(4), played a central regulatory role in multiple DNA damage repair and protection pathways in response to radiation stress. Since then, as a global regulator of extreme stress responses, IrrE had improved the stress resilience of exogenous hosts in several studies. The heterologous expression of irrE in Escherichia coli, Saccharomyces cerevisiae, Zymomonas mobilis could cause significant changes in the host’s transcriptome and proteome, and enhance tolerance to various stresses such as acid, salt, organic solvent, inhibitors in lignocellulose hydrolysates and high temperatures. IrrE and its mutants had been used as tolerance elements in the construction of highly-efficient microbial cell factory for fuel ethanol, organic acids, biopolymers, fuel cells, and bioremediation.