Natural Competence for DNA Transformation by Legionella pneumophila and Its Association with Expression of Type IV Pili
Natural Competence for DNA Transformation by Legionella pneumophila and Its Association with Expression of Type IV Pili
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DOI：
10.1128/jb.181.5.1395-1402.1999
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发表时间：
1999-03
影响因子：
3.2
通讯作者：
B. Stone;Y. Kwaik
中科院分区：
文献类型：
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作者：
B. Stone;Y. Kwaik
我们最近描述了嗜肺军团菌（B）表面两种不同长度的皮利的表达。J. Stone和Y.阿布·奎克，感染。Immun. 66：1768-1775，1998）。长皮利的产生需要编码IV型菌毛蛋白的功能性菌毛EL基因座。由于淋球菌IV型皮利与DNA转化能力有关，我们检测了淋球菌的DNA转化能力。在允许IV型皮利表达的条件下，将嗜肺菌用于DNA转化。我们证明了L.嗜肺军团菌天然能够通过等基因染色体DNA和含有L.嗜肺菌DNA许多不同的L。pneumophila基因座能够转化L. pneumophila，包括gspA、ppa、asd和pilEL。当竞争DNA含有L.将嗜肺菌DNA或载体序列添加到细菌中，表明摄取特异性序列可能不参与DNA摄取。DNA转化的能力与IV型皮利的表达相关，并且IV型皮利表达缺陷的apilEL突变体不能进行DNA转化。通过重新引入可恢复IV型皮利产生的粘粒，突变体的感受态互补得以恢复。通过引入pilELalone使突变体恢复最小的感受态。因此，L.嗜肺军团菌与IV型菌毛的表达相关，并导致L.将嗜肺菌DNA插入染色体中。由于IV型皮利的表达也有利于L.在将嗜肺菌感染到哺乳动物细胞和原生动物时，我们将IV型皮利CAP命名为（感受态和粘附相关的皮利）。
ABSTRACT We have recently described the expression of two pili of different lengths on the surface of Legionella pneumophila (B. J. Stone and Y. Abu Kwaik, Infect. Immun. 66:1768–1775, 1998). Production of long pili requires a functional pilEL locus, encoding a type IV pilin protein. Since type IV pili in Neisseria gonorrhoeaeare associated with competence for DNA transformation, we examined the competence of L. pneumophila for DNA transformation under conditions that allowed the expression of type IV pili. We show that L. pneumophila is naturally competent for DNA transformation by isogenic chromosomal DNA and by plasmid DNA containing L. pneumophila DNA. Many different L. pneumophila loci are able to transform L. pneumophilaafter addition of plasmid DNA, including gspA,ppa, asd, and pilEL. The transformation frequency is reduced when competing DNA containing either L. pneumophila DNA or vector sequences is added to the bacteria, suggesting that uptake-specific sequences may not be involved in DNA uptake. Competence for DNA transformation correlates with expression of the type IV pili, and apilEL mutant defective in expression of type IV pili is not competent for DNA transformation. Complementation of the mutant for competence is restored by the reintroduction of a cosmid that restores production of type IV pili. Minimal competence is restored to the mutant by introduction of pilELalone. We conclude that competence for DNA transformation in L. pneumophila is associated with expression of the type IV pilus and results in recombination of L. pneumophila DNA into the chromosome. Since expression of type IV pili also facilitates attachment of L. pneumophila to mammalian cells and protozoa, we designated the type IV pili CAP (for competence- and adherence-associated pili).