Ferrochelatase is present in Brucella abortus and is critical for its intracellular survival and virulence
Ferrochelatase is present in Brucella abortus and is critical for its intracellular survival and virulence
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DOI：
10.1128/iai.69.10.6225-6230.2001
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发表时间：
2001-10-01
影响因子：
3.1
通讯作者：
Ugalde, RA
中科院分区：
文献类型：
--
作者：
Almirón, M;Martínez, M;Ugalde, RA
布鲁氏菌是引起布鲁氏菌病的病原菌，布鲁氏菌病是一种动物疾病，也可以影响人类。虽然了解其发病机制对动物和人类的健康很重要，但与之相关的毒力因子却知之甚少。通过逃避细胞防御，已经发展出在吞噬细胞内生存的能力。它隐藏在液泡中，然后在那里复制，这表明它具有活跃的代谢。本研究的目的是更好地了解牛种布鲁氏菌的细胞内代谢。在一个B。在流产牛基因组测序项目中，鉴定并测序了编码与hemH同源的推定基因的克隆。氨基酸序列显示与亚铁螯合酶家族成员具有高度同源性。一个敲除突变体显示营养缺陷型氯化血红素，有缺陷的细胞内存活J774和HeLa细胞，并缺乏在BALB/c小鼠的毒力。通过用携带野生型hemH的质粒补充突变株来克服这种表型。这些数据表明，B。流产者合成其自身的血红素，并且也具有使用外部血红素来源的能力;然而，在细胞内，没有足够的可用血红素来支持其细胞内代谢。结论铁螯合酶对B的增殖和细胞内存活是必需的。流产，因此也是慢性病的原因。
Brucella spp. are pathogenic bacteria that cause brucellosis, an animal disease which can also affect humans. Although understanding the pathogenesis is important for the health of animals and humans, little is known about virulence factors associated with it. In order for chronic disease to be established, Brucella spp. have developed the ability to survive inside phagocytes by evading cell defenses. It hides inside vacuoles, where it then replicates, indicating that it has an active metabolism. The purpose of this work was to obtain better insight into the intracellular metabolism of Brucella abortus. During a B. abortus genomic sequencing project, a clone coding a putative gene homologous to hemH was identified and sequenced. The amino acid sequence revealed high homology to members of the ferrochelatase family. A knockout mutant displayed auxotrophy for hemin, defective intracellular survival inside J774 and HeLa cells, and lack of virulence in BALB/c mice. This phenotype was overcome by complementing the mutant strain with a plasmid harboring wild-type hemH. These data demonstrate that B. abortus synthesizes its own heme and also has the ability to use an external source of heme; however, inside cells, there is not enough available heme to support its intracellular metabolism. It is concluded that ferrochelatase is essential for the multiplication and intracellular survival of B. abortus and thus for the establishment of chronic disease as well.