Pherotype Polymorphism in Streptococcus pneumoniae Has No Obvious Effects on Population Structure and Recombination.
Pherotype Polymorphism in Streptococcus pneumoniae Has No Obvious Effects on Population Structure and Recombination.
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DOI：
10.1093/gbe/evx188
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发表时间：
2017-10-01
影响因子：
3.3
通讯作者：
Rozen DE
中科院分区：
文献类型：
--
作者：
Miller EL;Evans BA;Cornejo OE;Roberts IS;Rozen DE
革兰氏阳性病原体肺炎链球菌中的自然转化发生在细胞变得“感受态”时，所述感受态是响应于由comC基因座编码的称为感受态刺激肽（CSP）的分泌肽信号的高细胞外浓度而诱导的状态。已知两种主要的CSP信号类型（表型）主导菌株间的表型多样性。使用4，089个完全测序的肺炎球菌基因组，我们证实肺炎球菌群体具有高度的遗传结构，并且在不同的群体中，在表型频率上存在显着差异;大多数仅携带单一表型。此外，我们发现，这两个占主导地位的pherotypes的相对频率显着变化在一个小范围内跨地理站点。已经有不同的观点认为，表型或者促进表达相同表型的细胞之间的遗传交换，或者相反地，它们促进携带不同表型的菌株之间的重组。我们试图区分这些假设，使用生物信息学的方法，通过估计重组频率内和之间的表型在4,089全基因组。尽管潜在的人口结构，我们观察到广泛的重组人群之间，此外，我们发现显着更高的（虽然边际）的遗传交换率菌株表达不同的表型之间的分离株携带相同的表型。我们的研究结果表明，pherotypes不限制，甚至可能略有促进，菌株之间的重组，然而，这些边际效应表明更可能的可能性，CSP多态性的原因在于其对转化的影响之外。我们的研究结果表明，CSP的平衡多态性并没有因果关系的群体分化的基础。因此，当携带不同表型的菌株在共定殖期间彼此相遇时，可以不受限制地进行遗传交换。
Natural transformation in the Gram-positive pathogen Streptococcus pneumoniae occurs when cells become “competent,” a state that is induced in response to high extracellular concentrations of a secreted peptide signal called competence stimulating peptide (CSP) encoded by the comC locus. Two main CSP signal types (pherotypes) are known to dominate the pherotype diversity across strains. Using 4,089 fully sequenced pneumococcal genomes, we confirm that pneumococcal populations are highly genetically structured and that there is significant variation among diverged populations in pherotype frequencies; most carry only a single pherotype. Moreover, we find that the relative frequencies of the two dominant pherotypes significantly vary within a small range across geographical sites. It has been variously proposed that pherotypes either promote genetic exchange among cells expressing the same pherotype, or conversely that they promote recombination between strains bearing different pherotypes. We attempt to distinguish these hypotheses using a bioinformatics approach by estimating recombination frequencies within and between pherotypes across 4,089 full genomes. Despite underlying population structure, we observe extensive recombination between populations; additionally, we found significantly higher (although marginal) rates of genetic exchange between strains expressing different pherotypes than among isolates carrying the same pherotype. Our results indicate that pherotypes do not restrict, and may even slightly facilitate, recombination between strains; however, these marginal effects suggest the more likely possibility that the cause of CSP polymorphism lies outside of its effects on transformation. Our results suggest that the CSP balanced polymorphism does not causally underlie population differentiation. Therefore, when strains carrying different pherotypes encounter one another during cocolonization, genetic exchange can occur without restriction.
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影响因子：
5.4
作者：
Croucher NJ;Hanage WP;Harris SR;McGee L;van der Linden M;de Lencastre H;Sá-Leão R;Song JH;Ko KS;Beall B;Klugman KP;Parkhill J;Tomasz A;Kristinsson KG;Bentley SD
通讯作者：
Bentley SD
影响因子：
3.6
作者：
Håvarstein, LS;Martin, B;Claverys, JP
通讯作者：
Claverys, JP
影响因子：
3.3
作者：
Croucher NJ;Chewapreecha C;Hanage WP;Harris SR;McGee L;van der Linden M;Song JH;Ko KS;de Lencastre H;Turner C;Yang F;Sá-Leão R;Beall B;Klugman KP;Parkhill J;Turner P;Bentley SD
通讯作者：
Bentley SD
影响因子：
4.5
作者：
Croucher NJ;Mitchell AM;Gould KA;Inverarity D;Barquist L;Feltwell T;Fookes MC;Harris SR;Dordel J;Salter SJ;Browall S;Zemlickova H;Parkhill J;Normark S;Henriques-Normark B;Hinds J;Mitchell TJ;Bentley SD
通讯作者：
Bentley SD
影响因子：
4.9
作者：
Duesberg, Christoph B.;Malhotra-Kumar, Surbhi;Pletz, Mathias W. R.
通讯作者：
Pletz, Mathias W. R.