How an essential Zn2Cys6 transcription factor PoxCxrA regulates cellulase gene expression in ascomycete fungi?
How an essential Zn2Cys6 transcription factor PoxCxrA regulates cellulase gene expression in ascomycete fungi?
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重要的 Zn2Cys6 转录因子 PoxCxrA 如何调节子囊菌真菌中的纤维素酶基因表达？
DOI：
10.1186/s13068-019-1444-5
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发表时间：
2019-05-03
影响因子：
6.3
通讯作者：
Feng, Jia-Xun
中科院分区：
文献类型：
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作者：
Liao, Lu-Sheng;Li, Cheng-Xi;Feng, Jia-Xun
研究背景土壤中的子囊菌能产生降解植物生物量的酶，以促进植物对外源胁迫的养分和能量吸收。这是由一个复杂的信号网络控制的，但调控机制知之甚少。研究发现，一个重要的锌2Cys 6转录因子（TF）PoxCxrA是青霉（Penicillium）产生纤维素酶和木聚糖酶所必需的。通过RNA测序、DNA酶I足迹实验和体外电泳迁移率变动分析进一步鉴定了PoxCxrA的全基因组调节子和DNA结合序列。此外，一个最小的DNA结合结构域在PoxCxrA recognized.ResultsA的1970成员的PoxCxrA调节子被确定inP. pasticum，它被显示，PoxCxrA调节基因编码的主要植物细胞壁降解酶的表达，以及重要的纤维糊精和/或葡萄糖转运蛋白。有趣的是，PoxCxrA正调控已知重要的TFPoxClrB的表达。DNA酶I足迹实验和体外电泳迁移率变动分析进一步表明，PoxCxrA直接结合不同核酸序列的PoxClr和纤维二糖水解酶基因bh 1（POX 05587/Cel 7A-2）的启动子区。值得注意的是，PoxCxrA自身调节PoxCxrA基因的表达。结论PoxCxrA可通过与纤维素酶基因和调节基因PoxClrB的启动子结合，直接调控纤维素酶基因和调节基因PoxClrB的表达。这项工作扩展了已知被Zn 2Cys 6 TF识别的DNA结合基序的多样性，并展示了真菌纤维素酶基因表达的新调控机制。
BackgroundSoil ascomycete fungi produce plant-biomass-degrading enzymes to facilitate nutrient and energy uptake in response to exogenous stress. This is controlled by a complex signal network, but the regulatory mechanisms are poorly understood. An essential Zn2Cys6 transcription factor (TF) PoxCxrA was identified to be required for cellulase and xylanase production inPenicillium oxalicum. The genome-wide regulon and DNA binding sequences of PoxCxrA were further identified through RNA-Sequencing, DNase I footprinting experiments and in vitro electrophoretic mobility shift assays. Moreover, a minimal DNA-binding domain in PoxCxrA was recognised.ResultsA PoxCxrA regulon of 1970 members was identified inP.oxalicum, and it was displayed that PoxCxrA regulated the expression of genes encoding major plant cell wall-degrading enzymes, as well as important cellodextrin and/or glucose transporters. Interestingly, PoxCxrA positively regulated the expression of a known important TFPoxClrB. DNase I footprinting experiments and in vitro electrophoretic mobility shift assays further revealed that PoxCxrA directly bound the promoter regions ofPoxClrBand a cellobiohydrolase genecbh1(POX05587/Cel7A-2) at different nucleic acid sequences. Remarkably, PoxCxrA autoregulated its ownPoxCxrAgene expression. Additionally, a minimal 42-amino-acid PoxCxrA DNA-binding domain was identified.ConclusionPoxCxrA could directly regulate the expression of cellulase genes and the regulatory genePoxClrBvia binding their promoters at different nucleic acid sequences. This work expands the diversity of DNA-binding motifs known to be recognised by Zn2Cys6 TFs, and demonstrates novel regulatory mechanisms of fungal cellulase gene expression.