钝齿棒杆菌FarR对精氨酸生物合成基因簇转录水平的影响及其与ArgR的关系

Effect of FarR on transcriptional levels of arginine biosynthetic genes in Corynebacterium crenatum AS 1.542 and its relationship with ArgR

摘要:

摘要:【目的】FarR蛋白可参与棒杆菌精氨酸生物合成途径中相关基因的调控，但具体机制不清楚。本研究通过比较钝齿棒杆菌farR、argR单敲除株和farR与argR双敲除株Arg 生物合成途径中相关基因转录水平的变化来揭示FarR蛋白功能及其与ArgR的内在关联性。【方法】采用无痕敲除方法构建了钝齿棒杆菌farR单敲除株和farR与argR双敲除株;采用荧光定量PCR方法分析了farR、argR敲除及其组合敲除后精氨酸生物合成途径相关基因在转录水平的变化。【结果】在ArgR蛋白缺失的情况下，FarR可能发挥正调控功 能;在ArgR存在时，敲除farR，目标基因的转录水平改变存在不一致性，表现出上调、下调或无影响。【结论】钝齿棒杆菌中FarR和ArgR在精氨酸生物合成途径的调控中存在关联性。

关键词:关键词:钝齿棒杆菌，farR基因，argR基因，精氨酸，荧光定量PCR

Abstract:

Abstract:［Objective］ The FarR protein was involved in the regulation of arginine biosynthetic pathway in corynebacterium，but the regulation mechanism of FarR protein and its relationship with the negative regulator ArgR have never been reported．In this work，we constructed two deletion mutants: C． crenatum △farR and C．crenatum △argR △farR，and investigated the FarR function and its relationship with ArgR through the determination of transcriptional levels of arginine biosynthetic genes in four strains，including C．crenatum △argR constructed in previous work.［Methods］We used marker-less knockout technology to construct C．crenatum △farR and C．crenatum △argR△farR，and compared the transcriptional levels of the arginine biosynthetic genes in three mutant strains with those of the wild type strain using real-time fluorescence quantitative PCR.［Ｒesults］The results of ＲT-qPCR indicate that，in the absence of ArgR，FarR acted as a positive regulator．When farR gene was knockout alone，the transcriptional levels of arginine biosynthetic genes appeared up-regulated，down-regulated or no influence．［Conclusion］FarR and ArgＲ are involved together in the regulation of arginine biosynthetic pathway of C．crenatum．

Key words:Keywords: Corynebacterium crenatum，farR gene，argR gene，arginine，real-time fluorescence quantitative PCR