Novel type IV secretion system involved in propagation of genomic islands
Novel type IV secretion system involved in propagation of genomic islands
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DOI：
10.1128/jb.01327-06
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发表时间：
2007-02-01
影响因子：
3.2
通讯作者：
Hood, Derek W.
中科院分区：
文献类型：
--
作者：
Juhas, Mario;Crook, Derrick W.;Hood, Derek W.
IV型分泌系统(T4SS)介导水平基因转移，从而有助于基因组可塑性、感染性病原体的进化、抗生素耐药性和其他毒力特征的传播。流感嗜血杆菌基因组岛ICEHin1056的一个基因簇已被鉴定为参与基因组岛繁殖的T4SS。这种T4SS是新颖的，在进化上与前面描述的系统相去甚远。突变分析表明，该系统的关键基因失活导致了T4SS所提供的表型性状的丧失。在该T4SS突变的10个突变体中有7个不表达IV型分泌物菌毛。相应地，基因的破坏导致与亲本菌株相比接合频率降低高达100,000倍。此外，该T4SS的表达受到其组成部分之一的tfc24基因的正调控。我们的结论是，该基因簇代表了一个新的T4SS家族，参与了基因组岛的繁殖。
Type IV secretion systems (T4SSs) mediate horizontal gene transfer, thus contributing to genome plasticity, evolution of infectious pathogens, and dissemination of antibiotic resistance and other virulence traits. A gene cluster of the Haemophilus influenzae genomic island ICEHin1056 has been identified as a T4SS involved in the propagation of genomic islands. This T4SS is novel and evolutionarily distant from the previously described systems. Mutation analysis showed that inactivation of key genes of this system resulted in a loss of phenotypic traits provided by a T4SS. Seven of 10 mutants with a mutation in this T4SS did not express the type IV secretion pilus. Correspondingly, disruption of the genes resulted in up to 100,000-fold reductions in conjugation frequencies compared to those of the parent strain. Moreover, the expression of this T4SS was found to be positively regulated by one of its components, the tfc24 gene. We concluded that this gene cluster represents a novel family of T4SSs involved in propagation of genomic islands.