Cai Pengli, Wang Bang, Ji Jingxiao, Jiang Yongsheng, Wan Li, Tian Chaoguang, Ma Yanhe
From the Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China.
From the Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
J Biol Chem. 2015 Jan 9;290(2):788-96. doi: 10.1074/jbc.M114.609875. Epub 2014 Nov 14.
Neurospora crassa recently has become a novel system to investigate cellulase induction. Here, we discovered a novel membrane protein, cellodextrin transporter-like protein 1 (CLP1; NCU05853), a putative cellodextrin transporter-like protein that is a critical component of the cellulase induction pathway in N. crassa. Although CLP1 protein cannot transport cellodextrin, the suppression of cellulase induction by this protein was discovered on both cellobiose and Avicel. The co-disruption of the cellodextrin transporters cdt2 and clp1 in strain Δ3βG formed strain CPL7. With induction by cellobiose, cellulase production was enhanced 6.9-fold in CPL7 compared with Δ3βG. We also showed that the suppression of cellulase expression by CLP1 occurred by repressing the expression of cellodextrin transporters, particularly cdt1 expression. Transcriptome analysis of the hypercellulase-producing strain CPL7 showed that the cellulase expression machinery was dramatically stimulated, as were the cellulase enzyme genes including the inducer transporters and the major transcriptional regulators.
粗糙脉孢菌最近已成为研究纤维素酶诱导的新型系统。在此,我们发现了一种新型膜蛋白,即纤维糊精转运蛋白样蛋白1(CLP1;NCU05853),它是一种假定的纤维糊精转运蛋白样蛋白,是粗糙脉孢菌纤维素酶诱导途径的关键组成部分。虽然CLP1蛋白不能转运纤维糊精,但在纤维二糖和微晶纤维素上均发现该蛋白对纤维素酶诱导有抑制作用。在Δ3βG菌株中,纤维糊精转运蛋白cdt2和clp1的共破坏形成了CPL7菌株。在纤维二糖诱导下,与Δ3βG相比,CPL7中的纤维素酶产量提高了6.9倍。我们还表明,CLP1对纤维素酶表达的抑制是通过抑制纤维糊精转运蛋白的表达,特别是cdt1的表达来实现的。对高产纤维素酶菌株CPL7的转录组分析表明,纤维素酶表达机制以及包括诱导物转运蛋白和主要转录调节因子在内的纤维素酶基因均受到显著刺激。