背景:对氧化应激的反应在几乎所有生物体和线粒体膜蛋白中都很普遍,BbOhmm,对昆虫真菌病原体的氧化应激反应和毒力产生负面影响,白僵菌.没有进一步的,然而,已知BbOhmm和这种现象是如何调节的。
结果:通过染色质免疫沉淀(ChIP)-qPCR分析鉴定并验证了三种调节氧化应激的Zn2Cys6转录因子(BbOsrR1,2和3)与BbOhmm启动子区域的结合,BbOsrR2显示最强的结合。BbOsrR1或BbOsrR3的靶向基因敲除导致BbOhmm表达减少,因此增加了对自由基生成化合物(H2O2和甲萘醌)的耐受性,而ΔBbOsrR2菌株显示BbOhmm表达增加,同时对这些化合物的耐受性降低。RNA和ChIP测序分析显示,BbOsrR1直接调控广泛的抗氧化和转录相关基因,对BbClp1细胞周期蛋白和BbOsrR2的表达产生负面影响。显示BbClp1定位于细胞核并负介导氧化应激反应。除了调节抗氧化和解毒基因外,BbOsrR2和BbOsrR3还被证明可以进入Fus3-MAPK途径。发现三种转录因子的结合基序在BbOhmm和其他靶基因的启动子区域中部分重叠。而BbOsrR1似乎独立运作,共免疫沉淀显示BbClp1,BbOsrR2和BbOsrR3之间形成复合物,BbClp1部分调节BbOsrR2的磷酸化。
结论:这些发现揭示了由BbOsrR1介导的调节网络和协调真菌氧化应激反应的BbClp1-BbOsrR2-BbOsrR3复合物的形成。
BACKGROUND: Response to oxidative stress is universal in almost all organisms and the mitochondrial membrane protein, BbOhmm, negatively affects oxidative stress responses and virulence in the insect fungal pathogen, Beauveria bassiana. Nothing further, however, is known concerning how BbOhmm and this phenomenon is regulated.
RESULTS: Three oxidative stress response regulating Zn2Cys6 transcription factors (BbOsrR1, 2, and 3) were identified and verified via chromatin immunoprecipitation (ChIP)-qPCR analysis as binding to the BbOhmm promoter region, with BbOsrR2 showing the strongest binding. Targeted gene knockout of BbOsrR1 or BbOsrR3 led to decreased BbOhmm expression and consequently increased tolerances to free radical generating compounds (H2O2 and menadione), whereas the ΔBbOsrR2 strain showed increased BbOhmm expression with concomitant decreased tolerances to these compounds. RNA and ChIP sequencing analysis revealed that BbOsrR1 directly regulated a wide range of antioxidation and transcription-associated genes, negatively affecting the expression of the BbClp1 cyclin and BbOsrR2. BbClp1 was shown to localize to the cell nucleus and negatively mediate oxidative stress responses. BbOsrR2 and BbOsrR3 were shown to feed into the Fus3-MAPK pathway in addition to regulating antioxidation and detoxification genes. Binding motifs for the three transcription factors were found to partially overlap in the promoter region of BbOhmm and other target genes. Whereas BbOsrR1 appeared to function independently, co-immunoprecipitation revealed complex formation between BbClp1, BbOsrR2, and BbOsrR3, with BbClp1 partially regulating BbOsrR2 phosphorylation.
CONCLUSIONS: These findings reveal a regulatory network mediated by BbOsrR1 and the formation of a BbClp1-BbOsrR2-BbOsrR3 complex that orchestrates fungal oxidative stress responses.