Sequence-specific binding by Aspergillus nidulans AflR, a C6 zinc cluster protein regulating mycotoxin biosynthesis
Sequence-specific binding by Aspergillus nidulans AflR, a C6 zinc cluster protein regulating mycotoxin biosynthesis
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DOI：
10.1046/j.1365-2958.1998.00907.x
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发表时间：
1998-06-01
影响因子：
3.6
通讯作者：
Adams, TH
中科院分区：
文献类型：
--
作者：
Fernandes, M;Keller, NP;Adams, TH
构巢曲霉aflR基因在60 kb基因簇内发现，该基因簇包括大约24个在黄曲霉毒素相关真菌毒素杂色曲霉素的产生中起作用的其他基因。先前的工作表明AflR是一种C（6）锌双核簇蛋白，其在曲霉属中是保守的。并且在激活其它簇基因的表达中作为途径特异性转录因子起作用。在本报告中，我们证明了A。构巢菌AflR（AnAflR）是一种45 kDa的蛋白质，其结合在几种黄曲霉毒素和杂色曲霉素簇基因（ste基因）的启动子区中发现的回文序列5’-TCG（N（5））CGA-3’。通过使用与编码β-葡糖醛酸糖苷酶（GUS）的细菌uidA基因的基因融合物检查stcU的1.1kb启动子区域中的三个TCG（N（5））CGA元件的贡献来评估该AnAflR结合位点的体内相关性。通过突变一个、两个或所有三个AnAflR结合元件并检查野生型aflR或Δ aflR A中的GUS活性，在nidulans菌株中，我们发现ste基因的激活需要AnAflR和至少一个TCG（NF（5））CGA AflR结合位点。
The Aspergillus nidulans aflR gene is found within a 60 kb gene cluster that includes approximate to 24 other genes that putatively function in the production of the aflatoxin-related mycotoxin sterigmatocystin. Previous work showed that AflR is a C(6) zinc binuclear cluster protein that is conserved across Aspergillus spp. and functions as a pathway-specific transcription factor in activating expression of other cluster genes. In this report, we demonstrate that A. nidulans AflR (AnAflR) is a 45 kDa protein that binds to the palindromic sequence 5'-TCG(N(5))CGA-3' found in the promoter regions of several aflatoxin and sterigmatocystin cluster genes (ste genes). The in vivo relevance of this AnAflR binding site was assessed by examining the contribution of the three TCG(N(5))CGA elements in the 1.1 kb promoter region of stcU using gene fusions with the bacterial uidA gene encoding beta-glucuronidase (GUS). By mutating one, two or all three of the AnAflR-binding elements and examining GUS activity in wild-type aflR or Delta aflR A. nidulans strains, we found that ste gene activation required both AnAflR and at least one TCG(NF(5))CGA AflR binding site.