Kohchi C, Toh-e A
Mol Gen Genet. 1986 Apr;203(1):89-94. doi: 10.1007/BF00330388.
Candida pelliculosa var. acetaetherius is a strain of yeast which can utilize cellobiose as the carbon source. From a gene library prepared from this yeast, the beta-glucosidase gene has been cloned in a S. cerevisiae host using a chromogenic substrate, 5-bromo-4-chloro-3-indolyl-beta-glucoside as an indicator. It was proved by Southern analysis that the DNA fragment carrying the beta-glucosidase gene originated from C. pelliculosa. beta-Glucosidase produced by S. cerevisiae transformants was secreted into the periplasmic space. In Candida, beta-glucosidase was not induced by cellobiose but was derepressed by lowering the concentration of glucose. The regulation of beta-glucosidase synthesis in S. cerevisiae carrying the cloned beta-glucosidase was not clear compared with that in Candida, however, the enzyme activity in low glucose medium (0.05%) was reproducibly higher than in high glucose medium (2%). We have found the sequence that controls the expression of the beta-glucosidase gene negatively in S. cerevisiae.
醋酸醚膜假丝酵母是一种能够利用纤维二糖作为碳源的酵母菌株。从该酵母制备的基因文库中，使用显色底物5-溴-4-氯-3-吲哚基-β-葡萄糖苷作为指示剂，在酿酒酵母宿主中克隆了β-葡萄糖苷酶基因。通过Southern分析证明，携带β-葡萄糖苷酶基因的DNA片段源自膜假丝酵母。酿酒酵母转化体产生的β-葡萄糖苷酶分泌到周质空间。在假丝酵母中，β-葡萄糖苷酶不会被纤维二糖诱导，但会因降低葡萄糖浓度而解除阻遏。与假丝酵母相比，携带克隆的β-葡萄糖苷酶的酿酒酵母中β-葡萄糖苷酶合成的调控尚不清楚，然而，低葡萄糖培养基（0.05%）中的酶活性可重复性地高于高葡萄糖培养基（2%）。我们已经找到了在酿酒酵母中负向控制β-葡萄糖苷酶基因表达的序列。
