Conserved and essential transcription factors for cellulase gene expression in ascomycete fungi
Conserved and essential transcription factors for cellulase gene expression in ascomycete fungi
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DOI：
10.1073/pnas.1200785109
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发表时间：
2012-05-08
影响因子：
11.1
通讯作者：
Glass, N. Louise
中科院分区：
文献类型：
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作者：
Coradetti, Samuel T.;Craig, James P.;Glass, N. Louise
丝状真菌的合理工程改造，以提高纤维素酶的生产受到阻碍，我们不完全的知识转录调控网络。因此，我们使用的模式丝状真菌粗糙脉孢菌，以寻找与纤维素解构相关的未表征的转录因子。一个N的屏幕。Crassa转录因子缺失收集鉴定了两种未表征的锌双核簇转录因子（CLR-1和CLR-2），它们是生长和对纤维素的酶活性所需的，但不是生长或对木聚糖的半纤维素酶活性所需的。转录谱与下一代测序方法完善了我们对N。crassa对纤维素的转录应答，并证明了clr-1和clr-2是大部分应答所需的，包括诱导所有主要的纤维素酶和一些主要的半纤维素酶基因。功能性的cclr-1对clr-2的表达和纤维二糖的有效利用是必需的。系统发育分析表明，在大多数能够降解纤维素的丝状子囊菌的基因组中，β-1和β-2是保守的。在构巢曲霉中，携带clr-2同源物（clrB）缺失的菌株未能诱导纤维素酶基因表达并且缺乏对Avicel的纤维素分解活性。在工业生产菌株中进一步操作该控制系统可以显著提高用于纤维素生物燃料生产的纤维素酶的产率。
Rational engineering of filamentous fungi for improved cellulase production is hampered by our incomplete knowledge of transcriptional regulatory networks. We therefore used the model filamentous fungus Neurospora crassa to search for uncharacterized transcription factors associated with cellulose deconstruction. A screen of a N. crassa transcription factor deletion collection identified two uncharacterized zinc binuclear cluster transcription factors (clr-1 and clr-2) that were required for growth and enzymatic activity on cellulose, but were not required for growth or hemicellulase activity on xylan. Transcriptional profiling with next-generation sequencing methods refined our understanding of the N. crassa transcriptional response to cellulose and demonstrated that clr-1 and clr-2 were required for the bulk of that response, including induction of all major cellulase and some major hemicellulase genes. Functional CLR-1 was necessary for expression of clr-2 and efficient cellobiose utilization. Phylogenetic analyses showed that CLR-1 and CLR-2 are conserved in the genomes of most filamentous ascomycete fungi capable of degrading cellulose. In Aspergillus nidulans, a strain carrying a deletion of the clr-2 homolog (clrB) failed to induce cellulase gene expression and lacked cellulolytic activity on Avicel. Further manipulation of this control system in industrial production strains may significantly improve yields of cellulases for cellulosic biofuel production.