Nogawa M, Goto M, Okada H, Morikawa Y
Department of Bioengineering, Nagaoka University of Technology, Niigata, Japan.
Curr Genet. 2001 Jan;38(6):329-34. doi: 10.1007/s002940000165.
L-Sorbose has previously been assumed to stimulate cellulase formation in an indirect manner, different from that of sophorose in Trichoderma reesei. Through Northern blot analysis however, L-sorbose was found to regulate coordinately six cellulase genes (including eg13, whose behavior has not been studied so far) at transcriptional level, as is the case with sophorose in T. reesei strains PC-3-7 and QM9414. Dot blot analysis showed that the proportions of each cellulase mRNA to cbh1 mRNA, the largest amount of mRNA transcribed in T. reesei, did not change when L-sorbose or sophorose was used as an inducer in the PC-3-7 and QM9414 strains. cbh2 and egl1 mRNAs were about 45-60% and 20-30% of the cbh1 transcript, whereas small amounts of mRNA, 1-2% of cbh1, were observed on other endoglucanase genes. Furthermore, the PC-3-7 strain showed an enhanced level of cellulase gene transcription, about two- and four- to six-fold higher than that of the QM9414 strain with sophorose and L-sorbose, respectively.
以前人们认为L-山梨糖以一种不同于里氏木霉中槐糖的间接方式刺激纤维素酶的形成。然而，通过Northern印迹分析发现，L-山梨糖在转录水平上协同调节六个纤维素酶基因（包括eg13，其行为迄今尚未研究），里氏木霉PC-3-7和QM9414菌株中的槐糖也是如此。斑点印迹分析表明，在PC-3-7和QM9414菌株中以L-山梨糖或槐糖作为诱导剂时，每种纤维素酶mRNA与里氏木霉中转录量最大的cbh1 mRNA的比例没有变化。cbh2和egl1 mRNA分别约为cbh1转录本的45-60%和20-30%，而在其他内切葡聚糖酶基因上观察到少量mRNA，占cbh1的1-2%。此外，PC-3-7菌株的纤维素酶基因转录水平增强，分别比使用槐糖和L-山梨糖的QM9414菌株高约两倍和四至六倍。
