黄曲霉菌aflR基因启动子序列变异与黄曲霉毒素产生相关联  

Promoter Sequence Mutations in the aflR Gene of Aspergillus flavus are Correlated with the Production of Aflatoxin

作　　者：陈茹[1] 刘钟滨[1] 

机构地区：[1]同济大学医学院病原生物学教研室,上海200092

出　　处：《细胞生物学杂志》2006年第6期912-916,共5页Chinese Journal of Cell Biology

摘　　要：为探讨黄曲霉菌aflR基因启动子序列变异与黄曲霉毒素产生的关系,收集黄曲霉菌、米曲霉菌和寄生曲霉菌若干株。在有利于黄曲霉毒素产生的条件下培养后,提取各菌株的总RNA,RT-PCR法检测aflR基因的mRNA表达水平;并应用ELISA法检测各菌株产生黄曲霉毒素B1的情况。提取各菌株的基因组DNA,PCR扩增aflR基因启动子序列并测序。应用基因分析软件将不产毒素的黄曲霉菌与产毒黄曲霉菌的aflR基因启动子序列进行比较,找出不产毒菌株aflR基因启动子序列的变异位点。ELISA法和RT-PCR法结果表明,产毒的黄曲霉菌菌株均有明显的aflR基因转录,而在2株不产毒的黄曲霉菌菌株中,一株aflR基因无转录,另一株仅有较低水平的转录。序列比较结果表明,不产毒黄曲霉菌菌株的aflR基因启动子序列存在如下共同变异位点:-90、-236、-253、-262、-282位。米曲霉菌产生黄曲霉毒素B1和aflR基因转录的检测均为阴性,并且其aflR基因启动子序列中存在与上述不产毒黄曲霉菌菌株相同的变异位点。寄生曲霉菌产生黄曲霉毒素B1和aflR基因转录的检测均呈阳性,并且其aflR基因启动子序列的上述5个位点与产毒黄曲霉菌完全一致。在不产毒素的黄曲霉菌aflR基因启动子序列中发现了5个共同变异位点,实验结果提示这些变异位点可能与黄曲霉毒素的产生有关。For a better understanding of aflatoxin biosynthesis in some aspergillus strains, the mutation in the aflR （aflatoxin biosynthetic pathway regulatory gene） promoter region of none-aflatoxin B1-producing Aspergillusflavus （A.flavus） strains was investigated. For each strain cultured in medium suitable for aflatoxin production, the ELISA was performed to detect the aflatoxin B1 level and the total RNA was extracted and then the RT-PCR was carried out to evaluate the aflR mRNA level. The aflR promoter region was amplificated by PCR and then sequenced. Our experiment results showed that the aflR mRNA level was noticeably high in all the six aflatoxin B 1-producing A. flavus strains while the aflR mRNA level was either low or rare in the two none-aflatoxin B 1-producing A.flavus strains. Some mutation points at -90, -236, -253, -262 and -282 in the aflR promoter region were revealed in none-aflatoxin B 1-producing A.flavus strains through analyzing via a gene software. In addition, the experiment results from Aspergillus oryzae strains were coincident with those of none-aflatoxin B 1-producing A.flavus strains. And the results from the Aspergillus parasiticus strain were concordant with those of aflatoxin B 1-producing A.flavus strains. All these data indicate that one or some of the mutation sites described above in the aflR promoter region from A.flavus strains may be correlated to the aflatoxin production.

关 键 词：黄曲霉菌 黄曲霉毒素 aflR基因 启动子 序列变异 

分 类 号：Q933[生物学—微生物学]