Deslandes Vincent, Nash John H E, Harel Josée, Coulton James W, Jacques Mario
Groupe de Recherche sur les Maladies Infectieuses du Porc, Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, Québec, Canada.
BMC Genomics. 2007 Mar 13;8:72. doi: 10.1186/1471-2164-8-72.
To better understand effects of iron restriction on Actinobacillus pleuropneumoniae and to identify new potential vaccine targets, we conducted transcript profiling studies using a DNA microarray containing all 2025 ORFs of the genome of A. pleuropneumoniae serotype 5b strain L20. This is the first study involving the use of microarray technology to monitor the transcriptome of A. pleuropneumoniae grown under iron restriction.
Upon comparing growth of this pathogen in iron-sufficient versus iron-depleted medium, 210 genes were identified as being differentially expressed. Some genes (92) were identified as being up-regulated; many have confirmed or putative roles in iron acquisition, such as the genes coding for two TonB energy-transducing proteins and the hemoglobin receptor HgbA. Transcript profiling also led to identification of some new iron acquisition systems of A. pleuropneumoniae. Genes coding for a possible Yfe system (yfeABCD), implicated in the acquisition of chelated iron, were detected, as well as genes coding for a putative enterobactin-type siderophore receptor system. ORFs for homologs of the HmbR system of Neisseria meningitidis involved in iron acquisition from hemoglobin were significantly up-regulated. Down-regulated genes included many that encode proteins containing Fe-S clusters or that use heme as a cofactor. Supplementation of the culture medium with exogenous iron re-established the expression level of these genes.
We have used transcriptional profiling to generate a list of genes showing differential expression during iron restriction. This strategy enabled us to gain a better understanding of the metabolic changes occurring in response to this stress. Many new potential iron acquisition systems were identified, and further studies will have to be conducted to establish their role during iron restriction.
为了更好地理解铁限制对胸膜肺炎放线杆菌的影响并确定新的潜在疫苗靶点，我们使用包含胸膜肺炎放线杆菌5b型菌株L20基因组所有2025个开放阅读框（ORF）的DNA微阵列进行了转录谱研究。这是第一项涉及使用微阵列技术监测在铁限制条件下生长的胸膜肺炎放线杆菌转录组的研究。
在比较该病原体在铁充足与铁缺乏培养基中的生长情况时，鉴定出210个差异表达基因。一些基因（92个）被鉴定为上调；许多基因在铁获取中具有已证实或推测的作用，例如编码两种TonB能量转导蛋白和血红蛋白受体HgbA的基因。转录谱分析还导致鉴定出胸膜肺炎放线杆菌的一些新的铁获取系统。检测到编码可能的Yfe系统（yfeABCD）的基因，该系统与螯合铁的获取有关，以及编码假定的肠杆菌素型铁载体受体系统的基因。参与从血红蛋白获取铁的脑膜炎奈瑟菌HmbR系统同源物的开放阅读框显著上调。下调的基因包括许多编码含Fe-S簇蛋白或使用血红素作为辅因子的蛋白的基因。用外源铁补充培养基可恢复这些基因的表达水平。
我们利用转录谱分析生成了一份在铁限制期间差异表达的基因列表。该策略使我们能够更好地理解响应这种应激而发生的代谢变化。鉴定出许多新的潜在铁获取系统，必须进行进一步研究以确定它们在铁限制期间的作用。
