Evolution of an autotransporter:: Domain shuffling and lateral transfer from pathogenic Haemophilus to Neisseria
Evolution of an autotransporter:: Domain shuffling and lateral transfer from pathogenic Haemophilus to Neisseria
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DOI：
10.1128/jb.183.15.000-000.2001
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发表时间：
2001-08-01
影响因子：
3.2
通讯作者：
Golomb, M
中科院分区：
文献类型：
--
作者：
Davis, J;Smith, AL;Golomb, M
致病性流感嗜血杆菌菌株的基因组比 Rd KW20 (Rd) 更大，Rd KW20 是一种非致病性实验室菌株，其基因组已被测序。为了鉴定潜在的毒力基因，我们检查了 Int1 所拥有的基因，Int1 是一种来自脑膜炎患者的侵入性非包膜分离株，但在 Rd 中不存在，发现 Int1 有一个名为 lav 的新基因，预计编码毒力相关自转运蛋白 (AT) 的 AIDA-I/VirG/PerT 家族的成员。与 Inv 相关的是四核苷酸 GCAA 的多重重复，与表面的翻译相变化有关。由流感嗜血杆菌横向获得的分子，lav 的分布仅限于少数致病菌株，包括流感嗜血杆菌、埃及流感生物型和巴西紫癜分离株。 lav 的 DNA 序列与先前描述的脑膜炎奈瑟菌基因的 DNA 序列惊人地相似。序列比较表明，lav 是最近从嗜血杆菌转移到奈瑟氏球菌，就在脑膜炎奈瑟氏球菌和淋病奈瑟氏球菌分歧之前不久，预测编码乘客和 P 结构域的 lav 片段在 G+C 碱基含量上存在显着差异，支持了 AT 基因是通过融合起源于不同基因组的结构域而进化的观点。同源性和碱基序列比较表明，一种新的生物型 aegyptius AT 通过交换与 lav 过客结构域无关的序列，异常移动的 Inv 位点加入了越来越多从流感嗜血杆菌转移到奈瑟菌的基因列表。频繁的基因交换表明存在一个共同的高变应急基因库，可能有助于解释某些呼吸道病原体侵袭性的起源。
The genomes of pathogenic Haemophilus influenzae strains are larger than that of Rd KW20 (Rd), the nonpathogenic laboratory strain whose genome has been sequenced. To identify potential virulence genes, we examined genes possessed by Int1, an invasive nonencapsulated isolate from a meningitis patient, but absent from Rd, Int1 was found to have a novel gene termed lav, predicted to encode a member of the AIDA-I/VirG/PerT family of virulence-associated autotransporters (ATs), Associated with Inv are multiple repents of the tetranucleotide GCAA, implicated in translational phase variation of surface molecules, Laterally acquired by H. influenzae, lav is restricted in distribution to a few pathogenic strains, including H, influenzae biotype aegyptius and Brazilian purpuric fever isolates. The DNA sequence of lav is surprisingly similar to that of a gene previously described for Neisseria meningitidis. Sequence comparisons suggest that lav was transferred relatively recently from Haemophilus to Neisseria, shortly before the divergence of N. meningitidis and Neisseria gonorrhoeae, Segments of lav predicted to encode passenger and P-domains differ sharply in G+C base content, supporting the idea that AT genes have evolved by fusing domains which originated in different genomes, Homology and base sequence comparisons suggest that a novel biotype aegyptius AT arose by swapping an unrelated sequence for the passenger domain of lav, The unusually mobile Inv locus joins a growing list of genes transferred from H. influenzae to Neisseria. Frequent gene exchange suggests a common pool of hypervariable contingency genes and may help to explain the origin of invasiveness in certain respiratory pathogens.