Conjugative elements are widespread in bacteria and include plasmids and integrative and conjugative elements (ICEs). They transfer from donor to recipient cells via an element-encoded type IV secretion system. These elements interact with and utilize host functions for their lifecycles. We sought to identify essential host genes involved in the lifecycle of the integrative and conjugative element ICEBs1 of Bacillus subtilis. We constructed a library of strains for inducible knockdown of essential B. subtilis genes using CRISPR interference. Each strain expressed one guide RNA in ICEBs1. We induced partial interference of essential genes and identified those that caused an acute defect in acquisition of ICEBs1 by recipient cells. This screen revealed that reducing expression of genes needed for synthesis of cell wall teichoic acids caused a decrease in conjugation. Using three different ways to reduce their synthesis, we found that wall teichoic acids were necessary in both donors and recipients for efficient conjugative transfer of ICEBs1. Further, we found that depletion of wall teichoic acids caused cells involved in ICEBs1 conjugation to die, most likely from damage to the cell envelope. Our results indicate that wall teichoic acids help protect against envelope stress caused by active conjugation machines.

中文翻译：

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CRISPR 干扰筛选揭示了细胞壁磷壁酸在枯草芽孢杆菌结合中的作用

结合元件广泛存在于细菌中，包括质粒和整合结合元件 (ICE)。它们通过元素编码的 IV 型分泌系统从供体细胞转移到受体细胞。这些元素在其生命周期中与主机功能交互并利用它们。我们试图确定参与枯草芽孢杆菌整合和结合元件 ICE Bs1生命周期的必需宿主基因。我们构建了一个菌株库，用于使用 CRISPR 干扰诱导性敲除必需的枯草芽孢杆菌基因。每个菌株在 ICE Bs1中表达一个指导 RNA 。我们诱导了必需基因的部分干扰，并确定了那些导致 ICE Bs1获得急性缺陷的基因通过受体细胞。该筛选显示，减少合成细胞壁磷壁酸所需的基因表达导致结合减少。使用三种不同的方法来减少它们的合成，我们发现壁磷壁酸对于 ICE Bs1的有效共轭转移在供体和受体中都是必需的。此外，我们发现壁磷壁酸的消耗导致参与 ICE Bs1结合的细胞死亡，很可能是由于细胞包膜受损。我们的结果表明壁磷壁酸有助于防止由主动共轭机器引起的包络应力。