To rationally optimize the production of industrial enzymes by molecular means requires previous knowledge of the regulatory circuits controlling the expression of the corresponding genes. The genus Stachybotrys is an outstanding producer of cellulose-degrading enzymes. Previous studies isolated and characterized the lichenase-like/non-typical cellulase Cel12A of S. atra (AKA S. chartarum) belonging to glycosyl hydrolase family 12 (GH12). In this study, we used RT-qPCR to determine the pattern of expression of cel12A under different carbon sources and initial ambient pH. Among the carbon sources examined, rice straw triggered a greater increase in the expression of cel12A than 1% lactose or 0.1% glucose, indicating specific induction by rice straw. In contrast, cel12A was repressed in the presence of glucose even when combined with this inducer. The proximity of 2 adjacent 5′-CTGGGGTCTGGGG-3′ CreA consensus target sites to the translational start site of cel12A strongly suggests that the carbon catabolite repression observed is directly mediated by CreA. Ambient pH did not have a significant effect on cel12A expression. These findings present new knowledge on transcriptional regulatory networks in Stachybotrys associated with cellulose/hemicellulose depolymerization. Rational engineering of CreA to remove CCR could constitute a novel strategy for improving the production of Cel12A.

为了通过分子手段合理优化工业酶的生产，需要事先了解控制相应基因表达的调控回路。Stachybotrys属是纤维素降解酶的杰出生产者。先前的研究分离并表征了属于糖基水解酶家族 12 (GH12)的S. atra (AKA S. chartarum )的地衣酶样/非典型纤维素酶 Cel12A 。在这项研究中，我们使用 RT-qPCR 来确定cel12A在不同碳源和初始环境 pH 值下的表达模式。在检查的碳源中，稻草引发了cel12A表达的更大增加大于 1% 乳糖或 0.1% 葡萄糖，表明稻草特异性诱导。相比之下，cel12A在葡萄糖存在的情况下即使与这种诱导剂结合也被抑制。2 个相邻的 5'-CTGGGGTCTGGGG-3' CreA 共有靶位点与 cel12A 的翻译起始位点的接近强烈表明观察到的碳分解代谢物抑制是由 CreA 直接介导的。环境 pH 值对cel12A表达没有显着影响。这些发现提供了关于与纤维素/半纤维素解聚相关的水葡萄属转录调控网络的新知识。CreA 去除 CCR 的合理工程可以构成提高 Cel12A 产量的新策略。