Quorum-sensing regulation of the production of blp bacteriocins in Streptococcus thermophilus
Quorum-sensing regulation of the production of blp bacteriocins in Streptococcus thermophilus
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DOI：
10.1128/jb.00966-07
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发表时间：
2007-10-01
影响因子：
3.2
通讯作者：
Hols, Pascal
中科院分区：
文献类型：
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作者：
Fontaine, Laetitia;Boutry, Celine;Hols, Pascal
在嗜热链球菌LMG 18311、CNRZ 1066和LMD-9的基因组序列中鉴定的blp基因簇显示11类细菌素基因座的所有特征。在本研究中，我们发现，blp（St）基因座仅在菌株LMD-9中具有完全功能，并调节抑制菌株LMG 18311和CNRZ 1066的抗菌肽的产生。LMD-9的blp（St）簇包含23个基因，这些基因在转录上组织在6个操纵子中：blpABC（St）（肽转运蛋白基因和信息素基因）; blpRH（St）（双组分调控系统基因）; blpD（St）-orf 1、blpU（St）-orf 3和blpE-F-St（细菌素前体和免疫基因）;以及blpG-X-St（未知功能）。除了调控单元blpRH（St）外，所有的操纵子都在转录水平上通过涉及成熟S.嗜热菌信息素BIpC*（BlpC*st），其在细胞外检测为两种活性形式（30和19个氨基酸）。这些操纵子的转录差异取决于生长阶段和信息素浓度。它们都含有一个基序，在其映射的启动子区域，可以作为反应调节BlpR（St）的结合位点的两个不完美的直接重复。通过构建缺失突变体，菌株LMD-9的blp（St）位点被证明编码与细菌素产生、群体感应调节和免疫相关的所有基本功能。
The blp gene cluster identified in the genome sequences of Streptococcus thermophilus (blp,,) LMG18311, CNRZ1066, and LMD-9 displays all the characteristics of a class 11 bacteriocin locus. In the present study, we showed that the blp(St) locus is only fully functional in strain LMD-9 and regulates the production of antimicrobial peptides that inhibit strains LMG18311 and CNRZ1066. The blp(St) cluster of LMD-9 contains 23 genes that are transcriptionally organized in six operons: blpABC(St) (peptide transporter genes and pheromone gene); blpRH(St) (two-component regulatory system genes); blpD(St)-orf1, blpU(St)-orf3, and blpE-F-St (bacteriocin precursors and immunity genes); and blpG-X-St (unknown function). All the operons, except the regulatory unit blpRH(St), were shown to be coregulated at the transcriptional level by a quorum-sensing mechanism involving the mature S. thermophilus pheromone BIpC* (BlpC*st), which was extracellularly detected as two active forms (30 and 19 amino acids). These operons are differentially transcribed depending on growth phase and pheromone concentration. They all contain a motif with two imperfect direct repeats in their mapped promoter regions that could serve as binding sites of the response regulator BlpR(St). Through the construction of deletion mutants, the blp(St) locus of strain LMD-9 was shown to encode all the essential functions associated with bacteriocin production, quorum-sensing regulation, and immunity.