CLONING AND SEQUENCING OF A BORDETELLA-PERTUSSIS SERUM RESISTANCE LOCUS
CLONING AND SEQUENCING OF A BORDETELLA-PERTUSSIS SERUM RESISTANCE LOCUS
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DOI：
10.1128/iai.62.11.4727-4738.1994
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发表时间：
1994-11-01
影响因子：
3.1
通讯作者：
WEISS, AA
中科院分区：
文献类型：
--
作者：
FERNANDEZ, RC;WEISS, AA
我们鉴定了百日咳博德特氏菌的一种新毒力因子：血清耐药性。与大肠杆菌HB101相比，野生型百日咳博德特氏菌对正常人血清的经典途径、补体依赖性杀伤具有相对抵抗性。然而，百日咳博德特氏菌突变体（BPM2041）对小鼠的毒力较低，并且在先前未表征的bvg调节基因中插入了Tn5'lac，被发现对血清杀伤的敏感性比野生型至少高10倍。我们将这个位点命名为brk，表示博德特氏菌对杀伤的抵抗力。我们对 brk 基因座进行了克隆和测序，它编码两个不同转录的开放阅读框 (ORF)，称为 BrkA 和 BrkB。两种 ORP 都是血清抗性所必需的。在分隔两个 ORP 的 300 个碱基内以及每个 ORF 的上游是 BvgA 结合的推定位点。 BrkA 与百日咳杆菌粘附素有 29% 的同一性，除了保守的蛋白水解加工位点和外膜靶向信号外，还具有两个 RGD 基序。与百日咳杆菌粘附素一样，BrkA 参与粘附和侵袭。尽管有相似之处，但发现百日咳杆菌粘附素突变体对血清杀灭作用不如 BrkA 或 BrkB 突变体那么敏感。 BrkB 与大肠杆菌和麻风分枝杆菌中的 ORF 相似，并显示出与各种转运蛋白同源的结构域。根据其亲水特性，BrkB 被预测为细胞质膜蛋白。 Southern Biot 发现，在支气管败血博德特氏菌和副百日咳博德特氏菌中发现了 brk 序列，但在鸟博德特氏菌中没有发现。
We have characterized a new virulence factor in Bordetella pertussis: serum resistance. Compared with Escherichia coli HB101, wild-type B. pertussis was relatively resistant to classical-pathway, complement-dependent killing by normal human serum. However, a mutant of B. pertussis (BPM2041) which is less virulent in mice and which has Tn5'lac inserted in a previously uncharacterized bvg-regulated gene was found to be at least 10-fold more susceptible to serum killing than the wild type. We have named this locus brk, for Bordetella resistance to killing. We have cloned and sequenced the brk locus, and it encodes two divergently transcribed open reading frames (ORFs), termed BrkA and BrkB. Both ORPs are necessary for serum resistance. Within the 300 bases which separate the two ORPs and upstream of each ORF are putative sites for BvgA binding. BrkA shows 29% identity to pertactin and has two RGD motifs in addition to a conserved proteolytic processing site and an outer membrane targeting signal. Like pertactin, BrkA is involved in adherence and invasion. Despite the similarities, a pertactin mutant,vas found to be not as sensitive to serum killing as the BrkA or BrkB mutants. BrkB is similar to ORFs in E. coli and Mycobacterium leprae and displays domains of homology to various transporters. On the basis of its hydropathy profile, BrkB is predicted to be a cytoplasmic membrane protein. By Southern biot, brk sequences were found in Bordetella bronchiseptica and Bordetella parapertussis but not in Bordetella avium.