Laboratory of Molecular Immunology, Department of Microbiology, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile.
Vet Microbiol. 2012 Apr 23;156(1-2):1-7. doi: 10.1016/j.vetmic.2011.09.025. Epub 2011 Oct 1.
The genomic island 3 (GI-3) shared by Brucella melitensis and Brucella abortus contains 29 genes encoding mostly unknown proteins. Within this island, the open reading frames (ORFs) BAB1_0278 and BAB1_0263 are present, BAB1_0278 encodes a hypothetical protein of 64 amino acids sharing a domain with the GcrA superfamily, whereas the amino acid sequence of BAB1_0263 showed 42% identity with an iron regulated Lsr2 protein. We obtained one deletion mutant for each one of these ORFs present within the B. abortus GI-3 named BA-278 and BA-263, respectively. Both mutants were evaluated with respect to their ability to invade and replicate in nonprofessional and professional phagocytes (HeLa and J774.A1 cells) and their virulence in mice. Both mutants invaded efficiently HeLa and J774. A1 cells, however, 48-h post-infection the BA-278 mutant showed a lower intracellular persistence. The deletion of the ORF BAB1_0278, also affected the persistence of B. abortus in the spleens of mice, unlike to the deletion of the ORF BAB1_0263. These results allow us to conclude that BAB1_0278 ORF contributes to virulence of Brucella, since it is necessary to establish an optimal infectious process.
绵羊布鲁氏菌和流产布鲁氏菌共有基因组岛 3（GI-3），其中包含 29 个基因，这些基因大多编码未知蛋白。在该岛中，存在开放阅读框（ORF）BAB1_0278 和 BAB1_0263，BAB1_0278 编码一个由 64 个氨基酸组成的假定蛋白，其与 GcrA 超家族的一个结构域具有同源性，而 BAB1_0263 的氨基酸序列与铁调节的 Lsr2 蛋白具有 42%的同一性。我们获得了 B. abortus GI-3 中这两个 ORF 各自的缺失突变体，分别命名为 BA-278 和 BA-263。分别评估了这两个突变体在非专业和专业吞噬细胞（HeLa 和 J774.A1 细胞）中入侵和复制的能力及其在小鼠中的毒力。这两个突变体都有效地入侵了 HeLa 和 J774. A1 细胞，但在感染后 48 小时，BA-278 突变体的细胞内持续时间较低。ORF BAB1_0278 的缺失也影响了 B. abortus 在小鼠脾脏中的持续存在，而 ORF BAB1_0263 的缺失则没有。这些结果使我们得出结论，BAB1_0278 ORF 有助于布鲁氏菌的毒力，因为它是建立最佳感染过程所必需的。
