Refined analysis of the Campylobacter jejuni iron-dependent/independent Fur- and PerR-transcriptomes
Refined analysis of the Campylobacter jejuni iron-dependent/independent Fur- and PerR-transcriptomes
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DOI：
10.1186/s12864-015-1661-7
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发表时间：
2015-07-04
期刊：
影响因子：
4.4
通讯作者：
Stintzi, Alain
中科院分区：
文献类型：
--
作者：
Butcher, James;Handley, Rebecca A.;Stintzi, Alain
背景：空肠弯曲菌基因组中含有两个铁激活的Fur家族转录调控因子CjFur和CjPerR，它们分别负责调节铁的稳态和氧化应激。这两种转录调控因子此前都被认为参与了对空肠弯曲菌主要功能以外的多种功能的调控。为了进一步研究它们的调控网络，利用RNA-seq技术研究了空肠弯曲菌野生型、Delta fur、Delta perr和Delta fur等基因缺失突变体在铁充足和铁限制条件下的转录图谱。结果：在铁充足和铁限制条件下，至少有202个基因在至少一个突变体中差异表达，在铁限制条件下，至少有331个基因在至少一个突变体中差异表达。将本研究中描述的CjFur和CjPerR转录本与以前使用微阵列图谱鉴定的转录本进行比较，发现其比之前了解的更广泛。有趣的是，我们的结果表明CjFur/CjPerR似乎以一种相反的和铁不依赖的方式共同调节鞭毛生物发生基因的表达。此外，Delta Fur Delta PerR等基因缺失突变体显示CjFur和CjPerR在某些情况下可以相互补偿，这表明两种调控因子可能都会竞争结合特定的启动子。结论：CjFur和CjPerR的转录本比以前报道的要大。特别是，PerR的缺失导致了一大组基因在缺乏铁的情况下的差异表达，这表明CjPerR也可能以一种铁不依赖的方式调节基因，类似于已经证明的CjFur。此外，还发现了仅当CjFur和CjPerR都缺失时才有差异表达的基因亚集，其中包括似乎同时被CjFur激活和CjPerR抑制的基因。特别是，CjFur/CjPerR对鞭毛生物发生的铁不依赖的共同调节代表了这些蛋白质潜在的新的调节功能。这些发现代表了这两种转录调控因子在空肠弯曲菌中的其他共同调节模式。
Background: The genome of Campylobacter jejuni contains two iron activated Fur-family transcriptional regulators, CjFur and CjPerR, which are primarily responsible for regulating iron homeostasis and oxidative stress respectively. Both transcriptional regulators have been previously implicated in regulating diverse functions beyond their primary roles in C. jejuni. To further characterize their regulatory networks, RNA-seq was used to define the transcriptional profiles of C. jejuni NCTC11168 wild type, Delta fur, Delta perR and Delta fur Delta perR isogenic deletion mutants under both iron-replete and iron-limited conditions.Results: It was found that 202 genes were differentially expressed in at least one mutant under iron-replete conditions and 331 genes were differentially expressed in at least one mutant under iron-limited conditions. The CjFur and CjPerR transcriptomes characterized in this study were compared to those previously identified using microarray profiling and found to be more extensive than previously understood. Interestingly, our results indicate that CjFur/CjPerR appear to co-regulate the expression of flagellar biogenesis genes in an opposing and iron-independent fashion. Moreover the Delta fur Delta perR isogenic deletion mutant revealed that CjFur and CjPerR can compensate for each other in certain cases, suggesting that both regulators may compete for binding to specific promoters.Conclusions: The CjFur and CjPerR transcriptomes are larger than previously reported. In particular, deletion of perR results in the differential expression of a large group of genes in the absence of iron, suggesting that CjPerR may also regulate genes in an iron-independent manner, similar to what has already been demonstrated with CjFur. Moreover, subsets of genes were found which are only differentially expressed when both CjFur and CjPerR are deleted and includes genes that appear to be simultaneously activated by CjFur and repressed by CjPerR. In particular the iron-independent co-regulation of flagellar biogenesis by CjFur/CjPerR represents a potentially novel regulatory function for these proteins. These findings represent additional modes of co-regulation by these two transcriptional regulators in C. jejuni.