Suominen P L, Mäntylä A L, Karhunen T, Hakola S, Nevalainen H
Research Laboratories, Alko Ltd, Helsinki, Finland.
Mol Gen Genet. 1993 Dec;241(5-6):523-30. doi: 10.1007/BF00279894.
Four cellulase genes of Trichoderma reesei, cbh1, cbh2, egl1 and egl2, have been replaced by the amdS marker gene. When linear DNA fragments and flanking regions of the corresponding cellulase locus of more than 1 kb were used, the replacement frequencies were high, ranging from 32 to 52%. Deletion of the major cellobiohydrolase 1 gene led to a 2-fold increase in the production of cellobiohydrolase II; however, replacement of the cbh2 gene did not affect the final cellulase levels and deletion of egl1 or egl2 slightly increased production of both cellobiohydrolases. Based on our results, endoglucanase II accounts for most of the endoglucanase activity produced by the hypercellulolytic host strain. Furthermore, loss of the egl2 gene causes a significant drop in the filter paper-hydrolysing activity, indicating that endoglucanase II has an important role in the total hydrolysis of cellulose.
里氏木霉的四个纤维素酶基因，即cbh1、cbh2、egl1和egl2，已被amdS标记基因取代。当使用超过1 kb的相应纤维素酶基因座的线性DNA片段和侧翼区域时，替换频率很高，范围从32%到52%。主要的纤维二糖水解酶1基因的缺失导致纤维二糖水解酶II的产量增加了2倍；然而，cbh2基因的替换并未影响最终的纤维素酶水平，而egl1或egl2的缺失略微增加了两种纤维二糖水解酶的产量。根据我们的结果，内切葡聚糖酶II占高纤维素分解宿主菌株产生的内切葡聚糖酶活性的大部分。此外，egl2基因的缺失导致滤纸水解活性显著下降，表明内切葡聚糖酶II在纤维素的总水解中起重要作用。
