FG11 Division of Enteropathogenic bacteria and Legionella, Robert Koch Institute, Burgstrasse 37, 38855, Wernigerode, Germany.
ZBS 4 - Advanced Light and Electron Microscopy, Robert Koch Institute, Nordufer 20, 13353, Berlin, Germany.
Sci Rep. 2019 Jul 11;9(1):10023. doi: 10.1038/s41598-019-46347-w.
The Gram-positive bacterium Listeria monocytogenes occurs ubiquitously in the environment and infects humans upon ingestion. It encodes four PadR-like repressors, out of which LftR has been characterized previously and was shown to control gene expression in response to the antibiotic aurantimycin produced by other environmental bacteria. To better understand the PadR regulons of L. monocytogenes, we performed RNA-sequencing with mutants of the other three repressors LadR, LstR and Lmo0599. We show that LadR is primarily responsible for the regulation of the mdrL gene, encoding an efflux pump, while LstR and Lmo0599 mainly regulate their own operons. The lstR operon contains the lmo0421 gene, encoding a homolog of the RodA/FtsW protein family. However, this protein does not possess such functionality, as we demonstrate here. The lmo0599 operon contains two additional genes coding for the hypothetical trans-membrane proteins lmo0600 and lmo0601. A striking phenotype of the lmo0599 mutant is its impaired growth at refrigeration temperature. In light of these and other results we suggest that Lmo0599 should be renamed and propose LltR (listerial low temperature regulator) as its new designation. Based on the nature of the PadR target genes we assume that these repressors collectively respond to compounds acting on the cellular envelope.
革兰氏阳性细菌李斯特菌普遍存在于环境中，并在人类摄入后感染。它编码四个 PadR 样抑制剂，其中 LftR 之前已经被表征过，被证明可以控制抗生素 aurantimycin 的基因表达，抗生素 aurantimycin 是由其他环境细菌产生的。为了更好地了解李斯特菌的 PadR 调控子，我们对其他三个抑制剂 LadR、LstR 和 Lmo0599 的突变体进行了 RNA-seq 分析。我们表明 LadR 主要负责 mdrL 基因的调控，该基因编码一个外排泵，而 LstR 和 Lmo0599 主要调控它们自己的操纵子。lstR 操纵子包含 lmo0421 基因，编码 RodA/FtsW 蛋白家族的同源物。然而，正如我们在这里所证明的，这种蛋白质没有这样的功能。lmo0599 操纵子包含另外两个编码假设跨膜蛋白 lmo0600 和 lmo0601 的基因。lmo0599 突变体的一个显著表型是其在冷藏温度下的生长受损。鉴于这些和其他结果，我们建议将 Lmo0599 重新命名，并提议将其新名称命名为 LltR（李斯特氏低温调节剂）。基于 PadR 靶基因的性质，我们假设这些抑制剂共同响应作用于细胞包膜的化合物。
