Auchtung Jennifer M, Lee Catherine A, Garrison Katherine L, Grossman Alan D
Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Mol Microbiol. 2007 Jun;64(6):1515-28. doi: 10.1111/j.1365-2958.2007.05748.x. Epub 2007 May 18.
ICEBs1 is a mobile genetic element found in the chromosome of Bacillus subtilis. Excision and transfer of ICEBs1 is regulated by the global DNA damage response and intercellular peptide signalling. We identified and characterized a repressor, ImmR (formerly YdcN), encoded by ICEBs1. ImmR represses transcription of genes required for excision and transfer, and both activates and represses its own transcription. ImmR regulates transcription within ICEBs1 by binding to several sites in the region of DNA that contains promoters for both immR and xis (encoding excisionase). In addition, we found that ImmR confers immunity from acquisition of additional copies of ICEBs1. ImmR-mediated regulation serves to keep a single copy of ICEBs1 stably maintained in the absence of induction, allows a rapid response to inducing signals, and helps limit acquisition of additional copies of ICEBs1.
ICEBs1是一种存在于枯草芽孢杆菌染色体中的可移动遗传元件。ICEBs1的切除和转移受全局DNA损伤反应和细胞间肽信号传导调控。我们鉴定并表征了一种由ICEBs1编码的阻遏蛋白ImmR（以前称为YdcN）。ImmR抑制切除和转移所需基因的转录，并且既激活又抑制自身的转录。ImmR通过结合包含immR和xis（编码切除酶）启动子的DNA区域中的几个位点来调节ICEBs1内的转录。此外，我们发现ImmR赋予对获取额外ICEBs1拷贝的免疫性。ImmR介导的调控有助于在没有诱导的情况下稳定维持单个ICEBs1拷贝，允许对诱导信号做出快速反应，并有助于限制获取额外的ICEBs1拷贝。
