Department of Biological Sciences, College of Arts and Science, Florida International University, Miami, FL 33199, USA, Department of Molecular Microbiology and Infectious Diseases, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA, BioRG, School of Computing and Information Science, College of Engineering and Computing, Florida International University, Miami, FL 33199, USA, Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA and Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA.
Nucleic Acids Res. 2014 Jan;42(2):979-98. doi: 10.1093/nar/gkt942. Epub 2013 Oct 23.
Pathogenicity of Pseudomonas aeruginosa, a major cause of many acute and chronic human infections, is determined by tightly regulated expression of multiple virulence factors. Quorum sensing (QS) controls expression of many of these pathogenic determinants. Previous microarray studies have shown that the AmpC β-lactamase regulator AmpR, a member of the LysR family of transcription factors, also controls non-β-lactam resistance and multiple virulence mechanisms. Using RNA-Seq and complementary assays, this study further expands the AmpR regulon to include diverse processes such as oxidative stress, heat shock and iron uptake. Importantly, AmpR affects many of these phenotypes, in part, by regulating expression of non-coding RNAs such as rgP32, asRgsA, asPrrF1 and rgRsmZ. AmpR positively regulates expression of the major QS regulators LasR, RhlR and MvfR, and genes of the Pseudomonas quinolone system. Chromatin immunoprecipitation (ChIP)-Seq and ChIP-quantitative real-time polymerase chain reaction studies show that AmpR binds to the ampC promoter both in the absence and presence of β-lactams. In addition, AmpR directly binds the lasR promoter, encoding the QS master regulator. Comparison of the AmpR-binding sequences from the transcriptome and ChIP-Seq analyses identified an AT-rich consensus-binding motif. This study further attests to the role of AmpR in regulating virulence and physiological processes in P. aeruginosa.
铜绿假单胞菌是许多急性和慢性人类感染的主要原因，其致病性取决于多种毒力因子的严格调控表达。群体感应（QS）控制着许多这些致病决定因素的表达。以前的微阵列研究表明，AmpC β-内酰胺酶调节剂 AmpR，一种 LysR 家族转录因子的成员，也控制非β-内酰胺耐药性和多种毒力机制。本研究使用 RNA-Seq 和互补测定法，进一步扩展了 AmpR 调控组，包括各种过程，如氧化应激、热休克和铁摄取。重要的是，AmpR 通过调节非编码 RNA（如 rgP32、asRgsA、asPrrF1 和 rgRsmZ）的表达来影响许多这些表型。AmpR 正向调节主要 QS 调节剂 LasR、RhlR 和 MvfR 以及假单胞菌喹诺酮系统基因的表达。染色质免疫沉淀（ChIP）-Seq 和 ChIP-定量实时聚合酶链反应研究表明，AmpR 在缺乏和存在β-内酰胺的情况下均结合到 ampC 启动子上。此外，AmpR 直接结合编码 QS 主调节剂的 lasR 启动子。转录组和 ChIP-Seq 分析中 AmpR 结合序列的比较确定了一个富含 AT 的保守结合基序。本研究进一步证明了 AmpR 在调节铜绿假单胞菌毒力和生理过程中的作用。
