Identification of a novel LysR-type transcriptional regulator in Staphylococcus aureus that is crucial for secondary tissue colonization during metastatic bloodstream infection

Purpose: The goal of this study was to identify Staphylococcus aureus genes which are important during establishment of metastatic infections in bloodstream infections. Methods: Pooled mariner transposon mutant libraries were generated as previously described (PMID: 27185949). The libraries were sequenced on the Illumina HiSeq 2500 platform with the transposon-specific oligonucleotide primer Himar1-Seq. Illumina adapter sequences were removed via cutadapt version 1.2.1. The reads were filtered for size (>16 bp) and to contain the signature transposon inverted repeat. Reads were mapped to the Staphylococcus aureus 6850 genome (RefSeq accession NC_022222.1) by Bowtie2 v2.1.0. Identification of depleted and enriched mutants was performed via DESeq2 version 1.6.2. Results: S. aureus genes were identified which were upregulated or downregulated upon iduced expression of the LysR-type transcriptional regulator RSAU_000852 in Staphylococcus aureus 6850. Conclusions: Our study identifies a gene for a LysR-type transcription regulator, which is involved in metabolic adaptation of the pathogen during colonization of secondary infection sites in a bloodstream infection model. Overall design: S. aureus RNAseq was performed on wild-type S. aureus 6850, an RSAU_000852 deletion mutant, and a strain carrying anhydrous tetracycline-induced RSAU_000852 ORF. Experiments were performed in triplicates.

研究目的：本研究旨在鉴定血流感染中转移性感染建立过程中发挥关键作用的金黄色葡萄球菌（Staphylococcus aureus）基因。
研究方法：按照此前报道的方法（PMID: 27185949）构建合并的mariner转座子突变体文库。使用转座子特异性寡核苷酸引物Himar1-Seq，在Illumina HiSeq 2500平台上完成文库测序。通过cutadapt v1.2.1移除Illumina接头序列，对测序读段进行长度过滤（>16 bp），并筛选包含转座子反向重复特征序列的读段。使用Bowtie2 v2.1.0将读段比对至金黄色葡萄球菌6850的基因组（RefSeq登录号NC_022222.1）。通过DESeq2 v1.6.2鉴定丰度降低与富集的突变体。
研究结果：本研究鉴定了在金黄色葡萄球菌6850中，经诱导表达LysR型转录调控因子RSAU_000852后出现表达上调或下调的S. aureus基因。
研究结论：本研究鉴定出一个LysR型转录调控因子编码基因，该基因在血流感染模型中，参与病原体在继发感染部位定植过程中的代谢适应。
整体实验设计：以野生型金黄色葡萄球菌6850、RSAU_000852缺失突变株以及携带无水四环素诱导型RSAU_000852开放阅读框（ORF）的菌株为材料开展S. aureus RNA测序实验，所有实验均设置三次生物学重复。