A Novel Aerobactin Utilization Cluster in Vibrio vulnificus with a Gene Involved in the Transcription Regulation of the iutA Homologue
A Novel Aerobactin Utilization Cluster in Vibrio vulnificus with a Gene Involved in the Transcription Regulation of the iutA Homologue
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DOI：
10.1111/j.1348-0421.2005.tb03671.x
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发表时间：
2005-09
影响因子：
2.6
通讯作者：
T. Tanabe;Ayaka Naka;H. Aso;H. Nakao;S. Narimatsu;Y. Inoue;T. Ono;Shigeo Yamamoto
中科院分区：
文献类型：
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作者：
T. Tanabe;Ayaka Naka;H. Aso;H. Nakao;S. Narimatsu;Y. Inoue;T. Ono;Shigeo Yamamoto
我们证明创伤弧菌M2799在铁限制条件下利用好氧肌动蛋白作为外源铁载体生长，伴随着76 kDa可抑制铁的外膜蛋白的增加。随后，通过对M2799基因组文库应用Fur滴定分析方法，并进一步克隆候选基因周围的区域，我们鉴定了8.4kb的需氧肌动蛋白利用基因簇，该基因簇由5个基因组成，排列在三个不同的转录单位。通过破坏相应的基因，证实形成三基因操纵子的第一个单位(VatCDB)和单基因的第三个单位(IutA)分别编码一个ATP结合盒转运组件和76 kDa的铁好氧肌动蛋白受体。另一个单基因(IutR)的第二个单位，编码GntR转录抑制因子家族的同源基因。尽管第一个和第三个单位的转录受铁的调控，但iutR基因的转录与生长介质中的铁状态无关。构建了一个iutR干扰物，结合遗传互补实验表明，该基因编码iutA的转录抑制物。这是第一个涉及好氧肌动蛋白增强Iuta生产的调节基因的例子。
We demonstrated that Vibrio vulnificus M2799 utilizes aerobactin for growth as an exogenous siderophore under iron‐limiting conditions, concomitant with enhanced production of the 76‐kDa iron‐repressible outer membrane protein. Subsequently, by applying the Fur titration assay method to the M2799 genomic libraries followed by further cloning of the regions surrounding the candidate genes, we identified the 8.4‐kb aerobactin utilization gene cluster which consists of five genes arranged in three distinct transcriptional units. It was confirmed by disruption of the corresponding genes that the first unit forming a three‐gene operon (vatCDB) and the third unit of a single gene (iutA) encode an ATP‐binding cassette transport component and the 76‐kDa ferric aerobactin receptor, respectively. The second unit of another single gene (iutR), encodes a homologue of the GntR family of transcriptional repressors. Although transcription of the first and third units was iron‐regulated, the iutR gene was transcribed regardless of iron status in the growth medium. Construction of an iutR disruptant coupled with genetic complementation experiments suggested that the gene encodes a transcriptional repressor for iutA. This is the first example of a regulator gene involved in aerobactin‐enhanced production of IutA.