title: Transcriptional profiling of the two-component regulatory system VraSR in Staphylococcus aureus with low-level vancomycin resistance.
abstract: The objective of this study was to comprehensively identify the target genes regulated by the two-component regulatory system VraSR in Staphylococcus aureus and to clarify the role of VraSR in low-level vancomycin resistance. Expression of vraS was determined by real-time quantitative reverse transcriptase PCR (qRT-PCR). A clinical heterogeneous vancomycin-intermediate S. aureus (hVISA) strain B6D and a vancomycin-intermediate S. aureus (VISA) strain D7 that was induced from a meticillin-resistant S. aureus strain were selected to construct vraSR null mutants by allelic replacement. The vraSR-complemented strain B6D_c was also constructed by allelic replacement. Genes differentially expressed in the wild-type, vraSR null mutant and complemented strains were detected using RNA-Seq and were validated by qRT-PCR. Compared with vancomycin-susceptible S. aureus strains, expression of vraS was upregulated in all four isogenic hVISA strains. Vancomycin minimum inhibitory concentrations (MICs) in the vraSR null mutants B6D-ΔvraSR and D7-ΔvraSR were significantly lower than in the wild-type strains B6D and D7 and the complemented strain B6D_c. RNA-Seq and qRT-PCR data showed that expression of genes encoding FmtA protein, foldase protein PrsA, capsular polysaccharide biosynthesis glycosyltransferase, TcaA, a putative membrane protein, and six hypothetical proteins was down regulated in both vraSR-null mutants B6D-ΔvraSR and D7-ΔvraSR. Most of these differentially expressed proteins are involved in cell wall biosynthesis, which is associated with vancomycin resistance in S. aureus. In conclusion, VraSR plays an important role in S. aureus strains with low-level vancomycin resistance. PrsA, FmtA, glycosyltransferase and TcaA are regulated directly or indirectly by VraSR.
authors.affiliation: Department of Clinical Laboratory, Peking University People's Hospital, Beijing 100044, People's Republic of China.
authors.forename: Hongbin
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Clinical Laboratory, China Meitan General Hospital, Beijing 100028, People's Republic of China.
authors.forename: Zhujia
authors.initials: Z
authors.lastname: Xiong
authors.affiliation: Laboratory Medicine, Department of Clinical Medicine, Peking University Health Science Center, Beijing 100191, People's Republic of China.
authors.forename: Kuoyue
authors.initials: K
authors.lastname: Liu
authors.affiliation: Department of Clinical Laboratory, Peking University People's Hospital, Beijing 100044, People's Republic of China.
authors.forename: Shuguang
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Clinical Laboratory, Peking University People's Hospital, Beijing 100044, People's Republic of China.
authors.forename: Ruobing
authors.initials: R
authors.lastname: Wang
authors.affiliation: Department of Clinical Laboratory, Peking University People's Hospital, Beijing 100044, People's Republic of China.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Clinical Laboratory, Peking University People's Hospital, Beijing 100044, People's Republic of China.
authors.forename: Yawei
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Clinical Laboratory, Peking University People's Hospital, Beijing 100044, People's Republic of China. Electronic address: whuibj@163.com.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D017353:Gene Deletion; D020869:Gene Expression Profiling; D005816:Genetic Complementation Test; D006801:Humans; D008826:Microbial Sensitivity Tests; D060888:Real-Time Polymerase Chain Reaction; D017423:Sequence Analysis, RNA; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics*; D020713:Vancomycin Resistance
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C478170:VraR protein, Staphylococcus aureus; C478169:VraS protein, Staphylococcus aureus
keywords: Low-level vancomycin resistance; RNA-Seq; Staphylococcus aureus; VraSR