Hu Yang, Bi Jiannan, Hao Xiaoran, Chen Huang, Pan Jiao, Zhu Xudong
State Key Program of Microbiology, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
Wei Sheng Wu Xue Bao. 2013 Apr 4;53(4):354-62.
Use of renewable plant biomass is an active area in current biotechnology research. This report explores the cellulose-degradation system and the factors affecting cellulase gene expression in Chaetomium globosum NK102.
In the sequenced genome, we identified 10 cellulase genes by sequence homology alignment. We used a high-throughput sequencing technology (RNA-Seq) to monitor the differential expression of the genes under different culture conditions.
We observed that cellulase activity increased with time in the fungal cultures. Accordingly, transcription of the genes encoding cellobiohydrolase, cellobiose dehydrogenase and endoglucanase (cbh1, cdh and eglI) was higher than the others. Expression of the transcriptional repressors, ACE I and CreA, decreased with the time, whereas expression of Hap2/3/5 complex was upregulated. In different carbon sources, cellulase activity and their gene transcription were repressed by glucose and were activated by cellobiose. Sorbitol had no significant effect. Interestingly, light affected positively the expression of these cellulase genes.
Differential RNA-seq analysis can make preliminary exploration on the expression regulation of cellulase genes. Expression of the genes in C. globosum was determined by different culture conditions. This study has shown a molecular system of cellulose-degradation in C. globosum and provides information for interpretation of carbohydrate metabolism.
可再生植物生物质的利用是当前生物技术研究的一个活跃领域。本报告探讨了球毛壳菌NK102中的纤维素降解系统以及影响纤维素酶基因表达的因素。
在已测序的基因组中，我们通过序列同源性比对鉴定出10个纤维素酶基因。我们使用高通量测序技术（RNA测序）来监测不同培养条件下这些基因的差异表达。
我们观察到真菌培养物中的纤维素酶活性随时间增加。相应地，编码纤维二糖水解酶、纤维二糖脱氢酶和内切葡聚糖酶（cbh1、cdh和eglI）的基因转录高于其他基因。转录阻遏物ACE I和CreA的表达随时间下降，而Hap2/3/5复合体的表达上调。在不同碳源中，纤维素酶活性及其基因转录受到葡萄糖的抑制，并被纤维二糖激活。山梨醇没有显著影响。有趣的是，光照对这些纤维素酶基因的表达有积极影响。
差异RNA测序分析可以对纤维素酶基因的表达调控进行初步探索。球毛壳菌中这些基因的表达受不同培养条件的影响。本研究展示了球毛壳菌中纤维素降解的分子系统，并为解释碳水化合物代谢提供了信息。
