Fur regulates the expression of iron-stress genes in the cyanobacterium Synechococcus sp strain PCC 7942
Fur regulates the expression of iron-stress genes in the cyanobacterium Synechococcus sp strain PCC 7942
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DOI：
10.1099/13500872-142-6-1469
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发表时间：
1996-06-01
期刊：
影响因子：
2.8
通讯作者：
Straus, NA
中科院分区：
文献类型：
--
作者：
Ghassemian, M;Straus, NA
通过基于大肠杆菌的“体内阻遏试验”，从蓝细菌聚球藻属菌株PCC 7942中分离出“铁摄取调节”基因（Fur）的同源物。该测定使用了一种含有铁调节的蓝藻基因isiA的启动子区的铁调节基因构建体。与氯霉素乙酰转移酶的编码区融合。分离的基因编码的蛋白质与E.大肠杆菌，并含有推定的铁结合基序中发现的毛皮蛋白的紫色细菌。没有发现显着的相似性DxtR阻遏物，调节毒素的表达和铁载体生产革兰氏阳性菌。插入突变的克隆蓝藻毛皮基因导致创建的异等位基因突变体，显示缺铁症状，在铁充满介质中，包括组成性生产的黄氧还蛋白和异羟肟酸铁载体。未能消除野生型拷贝的毛皮基因的多倍体基因组的聚球藻7942意味着，在这个蓝藻毛皮可能有必要的功能，除了参与铁清除或光合电子传递的基因的调节。
A homologue of the 'ferric uptake regulation' gene (fur) was isolated from the cyanobacterium Synechococcus sp, strain PCC 7942 by an Escherichia coli-based 'in vivo repression assay'. The assay uses a reporter-gene construct containing the promoter region of the iron-regulated cyanobacterial gene isiA. fused to the coding region for chloramphenicol acetyltransferase. The isolated gene codes for a protein that has 41 % sequence similarity (36 % identity) to Fur from E. coli and contains the putative iron-binding motif found in the Fur proteins of purple bacteria. No significant similarity was found to the DxtR repressor that regulates the expression of toxin and siderophore production in Gram-positive bacteria. Insertional mutagenesis of the cloned cyanobacterial fur gene led to the creation of heteroallelic mutants that showed iron-deficiency symptoms in iron-replete medium, including the constitutive production of flavodoxin and of hydroxamate siderophores. Failure to eliminate wild-type copies of the fur gene from the polyploid genome of Synechococcus 7942 implies that in this cyanobacterium Fur may have essential functions in addition to the regulation of genes involved in iron scavenging or photosynthetic electron transport.