Phage-inducible islands in the Gram-positive cocci.
Phage-inducible islands in the Gram-positive cocci.
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DOI：
10.1038/ismej.2016.163
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发表时间：
2017-04
期刊：
影响因子：
--
通讯作者：
Penadés JR
中科院分区：
文献类型：
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作者：
Martínez-Rubio R;Quiles-Puchalt N;Martí M;Humphrey S;Ram G;Smyth D;Chen J;Novick RP;Penadés JR
SAPI是一个极其常见的噬菌体诱导的染色体岛(PICI)的聚集子家族，静止地驻留在葡萄球菌染色体上特定的At位点，并由辅助噬菌体诱导切除和复制。它们通常包装在由噬菌体病毒蛋白组成的小衣壳中，产生非常高的转移频率，通过干扰辅助噬菌体的繁殖而增强。由于SaPI代表了一种非常成功的生物学策略，许多天然金黄色葡萄球菌菌株含有两个或两个以上，我们假设类似的成分将在革兰氏阳性球菌中广泛存在。根据与聚合SAPI基因组的相似性，我们很容易在乳球菌和肺炎球菌/链球菌中鉴定出具有相似元件的大家族，以及粪肠球菌中的一些这样的元件。基于广泛的直系同源分析，我们发现四个不同属的PICI元素都代表着不同但平行的谱系，表明它们代表着朝着高度成功的生活方式的趋同进化。我们已经深入地表征了肠球菌元件EfCIV583，并表明它在功能和基因组组织上非常类似于SaPI，为扩大对这类元件的研究奠定了基础。总而言之，我们的发现极大地扩大了PICI家族的范围，包括了至少三个属的球菌的成分。
The SaPIs are a cohesive sub-family of extremely common phage-inducible chromosomal islands (PICIs) that reside quiescently at specific att sites in the staphylococcal chromosome and are induced by helper phages to excise and replicate. They are usually packaged in small capsids composed of phage virion proteins, giving rise to very high transfer frequencies, which they enhance by interfering with helper phage reproduction. As the SaPIs represent a highly successful biological strategy, with many natural Staphylococcus aureus strains containing two or more, we assumed that similar elements would be widespread in the Gram-positive cocci. On the basis of resemblance to the paradigmatic SaPI genome, we have readily identified large cohesive families of similar elements in the lactococci and pneumococci/streptococci plus a few such elements in Enterococcus faecalis. Based on extensive ortholog analyses, we find that the PICI elements in the four different genera all represent distinct but parallel lineages, suggesting that they represent convergent evolution towards a highly successful life style. We have characterized in depth the enterococcal element, EfCIV583, and have shown that it very closely resembles the SaPIs in functionality as well as in genome organization, setting the stage for expansion of the study of elements of this type. In summary, our findings greatly broaden the PICI family to include elements from at least three genera of cocci.