ACEI、ACEII和Xyr1是康氏木霉中调控纤维素酶基因表达的转录因子。体外实验已证实ACEI和Xyr1可与cbh1启动子上的287bp序列(-304bp--18bp)结合从而调控cbh1基因转录,但ACEII是否可与此序列结合仍未清楚。为进一步研究ACEII调控纤维素酶基因表达的机制,利用PCR技术扩增康氏木霉ACEII DNA结合区的基因序列,并使其在大肠杆菌中表达。凝胶迁移率移动试验表明ACEII DNA结合区不能与cbh1启动子的287bp序列结合。提示了康氏木霉cbh1基因在诱导表达时起调控作用的主要是Xyr1,而不是ACEII。这对阐明真菌纤维素酶基因表达调控的分子机制具有重要的意义。
ACEI,ACEII and Xyr1 are transcriptional factors that regulate cellulase gene expression in Trichoderma koningii.In vitro experiments have shown that ACEI and Xyr1 bind to the cbh1 promoter fragment(-304 to-18) and regulate the gene transcription.However,whether ACEII binds to this 287bp fragment is still unclear.To further elucidate the regulatory mechanism of ACEII for cellulase,DNA-binding domains of ACEII from T.Koningii were expressed in E.coli.It could not show binding to the cbh1 promoter fragment(-304 to-18) by electrophoresis mobility shift assays,suggesting that it is Xyr1 but not ACEII binds playing an essential role during induction of cbh1 gene transcription.