Surface Exclusion Revisited: Function Related to Differential Expression of the Surface Exclusion System of Bacillus subtilis Plasmid pLS20
Surface Exclusion Revisited: Function Related to Differential Expression of the Surface Exclusion System of Bacillus subtilis Plasmid pLS20
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DOI：
10.3389/fmicb.2019.01502
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发表时间：
2019-07-10
影响因子：
5.2
通讯作者：
Meijer, Wilfried J. J.
中科院分区：
文献类型：
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作者：
Gago-Cordoba, Cesar;Val-Calvo, Jorge;Meijer, Wilfried J. J.
在接合期间，遗传元件通过连接通道从细菌供体转移到受体细胞。它是导致抗生素耐药性传播的主要途径。缀合元件可以包含抑制其转移到已经携带该元件的细胞的排除系统。我们对排阻系统的有限了解主要基于革兰氏阴性菌的质粒。本文研究了革兰氏阳性枯草芽孢杆菌接合质粒pLS 20。我们证明，pLS 20包含一个排除系统，并确定了单一的基因负责排除，命名为SES（pLS 20），这是嵌入在共轭操纵子。Ses（pLS 20）是由革兰氏阳性菌接合元件编码的一个新的表面排斥蛋白家族的创始成员。我们表明，表面排斥的程度与sespLS20的表达水平相关，并且sespLS20在所有供体细胞中以基础低水平表达，但在接合细胞中高度表达。因此，pLS 20从缀合引发的供体细胞向未引发的供体或缀合引发的供体的转移分别被适度和非常有效地抑制。这种差异的调节，这似乎是一个保守的革兰氏阳性和革兰氏阴性起源的表面排斥系统的功能的后果进行了讨论。
During conjugation a genetic element is transferred from a bacterial donor to a recipient cell via a connecting channel. It is the major route responsible for the spread of antibiotic resistance. Conjugative elements can contain exclusion system(s) that inhibit its transfer to a cell already harboring the element. Our limited knowledge on exclusion systems is mainly based on plasmids of Gram-negative bacteria. Here we studied the conjugative plasmid pLS20 of the Gram-positive Bacillus subtilis. We demonstrate that pLS20 contains an exclusion system and identified the single gene responsible for exclusion, named ses(pLS20), which is embedded in the conjugation operon. Ses(pLS20) is the founding member of a novel family of surface exclusion proteins encoded by conjugative elements of Gram-positive origin. We show that the extent of surface exclusion correlates with the level of sespLS20 expression, and that sespLS20 is expressed at basal low-levels in all donor cells but becomes highly expressed in conjugating cells. Accordingly, the transfer of pLS20 from a conjugation-primed donor cell to an un-primed or conjugation-primed donor is inhibited moderately and very efficiently, respectively. The consequences of this differential regulation, which appears to be a conserved feature of surface exclusion systems of Gram-positive and Gram-negative origin, are discussed.