College of Life Sciences, Wuhan University, Wuhan 430072, China.
Res Microbiol. 2022 Jul-Sep;173(6-7):103956. doi: 10.1016/j.resmic.2022.103956. Epub 2022 May 13.
Maltocin P28, produced by Stenotrophomonas maltophilia P28, is an R-type phage tail-like bacteriocin (PTLB). Its gene cluster consists of 23 putative genes, including nine nonstructural genes and fourteen structural genes. In this work, three nonstructural genes, mpsA, mpsH and mpsR, were found to encode transcriptional regulators to control maltocin P28 synthesis. MpsA activated the transcription of mpsH and lysis genes. MpsH activated the transcription of structural genes. Under normal growth conditions, MpsR repressed the transcription of mpsA and the structural genes, as well as its own. When S. maltophilia P28 was treated with mitomycin C, an immediate and significant decrease in the amount of MpsR was observed, followed by derepressed expression of mpsA, mpsR and structural genes, a marked rise in the expression of all regulatory and structural genes, and finally a clear increase in the maltocin P28 production. Neither the recA gene nor the lexA gene was found to be involved in the induced synthesis of maltocin P28. Our study indicated that a unique mechanism regulates the expression of maltocin genes in S. maltophilia, representing a novel strategy for balancing the expression of PTLB genes in bacteria.
由嗜麦芽寡养单胞菌 P28 产生的麦芽糖菌素 P28 是一种 R 型噬菌体尾状细菌素 (PTLB)。其基因簇由 23 个假定基因组成，包括 9 个非结构基因和 14 个结构基因。在这项工作中，发现三个非结构基因 mpsA、mpsH 和 mpsR 编码转录调节因子，以控制麦芽糖菌素 P28 的合成。MpsA 激活 mpsH 和裂解基因的转录。MpsH 激活结构基因的转录。在正常生长条件下，MpsR 抑制 mpsA 和结构基因的转录，以及自身的转录。当嗜麦芽寡养单胞菌 P28 用丝裂霉素 C 处理时，观察到 MpsR 的含量立即显著下降，随后 mpsA、mpsR 和结构基因的表达被解除抑制，所有调节和结构基因的表达明显上升，最终麦芽糖菌素 P28 的产量明显增加。未发现 recA 基因或 lexA 基因参与麦芽糖菌素 P28 的诱导合成。我们的研究表明，一种独特的机制调节嗜麦芽寡养单胞菌中麦芽糖素基因的表达，代表了细菌中 PTLB 基因表达平衡的一种新策略。
