Regulation of recombination in Mycoplasma genitalium

生殖支原体重组的调控

• 批准号: 9371810
• 负责人: PATRICIA A TOTTEN
• 金额: $ 23.24万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-06-01 至 2019-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9371810
• 关键词: Affect; Antibiotic Therapy; Antibodies; Antibody Response; Antigenic Diversity; Antigenic Variation; Archives; Bacteria; Bacterial Adhesins; Biochemical; Biological Assay; Carbon Dioxide; Chromosomes; Chronic; Co-Immunoprecipitations; Complement; Complex; Cytoplasm; DNA Binding; DNA Repair; Disease; Environment; Enzymes; Filament; Funding; Future; Genes; Genetic; Genetic Recombination; Genetic Transcription; Genome; Goals; Growth; HIV; Human; Immune response; In Vitro; Infection; Inflammation; Length; Mass Spectrum Analysis; Mediating; Membrane Proteins; Methods; Mycoplasma genitalium; N-terminal; Neisseria gonorrhoeae; Organism; Pathway interactions; Phase; Physiological; Process; Production; Protein Isoforms; Proteins; Quantitative Reverse Transcriptase PCR; Regulation; Regulatory Pathway; Risk; Risk Factors; Sexual Transmission; Sigma Factor; Signal Transduction; Site; Son of Sevenless Proteins; Surface; Syndrome; System; Translation Initiation; Variant; Western Blotting; Woman; atmospheric carbon dioxide; clinically significant; environmental change; experimental study; in vivo; insight; men; mutant; novel; overexpression; pathogen; promoter; reproductive; reproductive tract; response

ABSTRACT Mycoplasma genitalium (MG) is a sexually transmitted pathogen, recognized as an important cause of several reproductive tract disease syndromes in men and women. Despite the inflammation and specific antibodies produced by the host, MG infections are often chronic, persisting for many months if not treated with effective antibiotic therapy. We and others have shown that the adhesins of MG, MgpB and MgpC, undergo phase and antigenic variation, likely contributing to evasion of the host immune response, persistence, and reinfection. MgpBC variation is mediated by a unique system of segmental reciprocal recombination between the mgpBC expression site and archived homologous partial copies of these genes, termed MgPars, located throughout the MG chromosome. However, the components required for mgpBC/MgPar recombination and their regulation are incompletely understood, in part due to the difficulty of working with this fastidious bacterium and the absence of a complete set of recombination genes and regulators in MG's tiny genome (580 kb). The goal of this proposal is to characterize the regulatory mechanism(s) mediating mgpBC/MgPar recombination, and therefore antigenic variation, in MG. Recently, we discovered that MG428 positively regulates recombination enzymes (recA, ruvA, and ruvB) and determined that this protein is a previously uncharacterized, extracytoplasmic function (ECF) sigma factor. We have also shown that, unique to MG, RecA is expressed as three distinct isoforms generated by alternative translation initiation: an active, full-length RecA and two inactive, N-terminally truncated versions of this protein. We propose that the small isoforms regulate mgpBC/MgPar recombination in MG by inhibiting the activity of full-length RecA. Further, we have determined that a novel protein of unknown function reduces antigenic and phase variation. We hypothesize that this putative membrane protein controls mgpBC/MgPar recombination in response to environmental signals. In addition, we have determined that growth in low CO2 enhances antigenic and phase variation rates. Building on these preliminary findings, we seek funding to explore the function of the truncated isoforms on full-length RecA activity (Aim 1), define the mechanism by which antigenic and phase variation is reduced by our newly identified membrane protein, including its putative network of interacting partners (Aim 2), and explore how CO2 and other environmental conditions affect this process (Aim 3). Finally we will investigate the effect of these conditions on recombination gene transcription and the expression of RecA isoforms, thereby defining the pathways controlling mgpBC/MgPar recombination in this organism. We anticipate that this study will reveal a novel, complex, and tightly regulated system of antigenic and phase variation mediating survival and evasion of the host immune response in a clinically significant and extremely fastidious pathogen.

抽象的 支原体生殖器（MG）是一种性传播的病原体，被认为是多个的重要原因 男性和女性生殖道疾病综合征。尽管发炎和特定抗体 由宿主产生的MG感染通常是慢性的，如果没有有效治疗，则持续多个月 抗生素疗法。我们和其他人表明，MG，MGPB和MGPC的粘附素，经历相位和 抗原变异，可能导致逃避宿主免疫反应，持久性和再感染。 MGPBC变化是由MGPBC之间的分段相互重组系统介导的 这些基因的表达位点和存档的同源部分副本，称为MGPARS，位于整个 MG染色体。但是，MGPBC/MGPAR重组所需的组件及其 调节是不完全理解的，部分原因是使用这种挑剔的细菌和 在MG的微小基因组（580 Kb）中，缺乏一组重组基因和调节剂。目标 该提议的特征是介导MGPBC/MGPAR重组的调节机制和 因此，抗原变异，以毫克为单位。最近，我们发现MG428积极调节重组 酶（RECA，RUVA和RUVB），并确定该蛋白是一种先前未表征的， 外质功能（ECF）Sigma因子。我们还表明，MG独有的RECA表示为 通过替代翻译起始产生的三种不同的同工型：一个活跃的，全长的RECA和两个 该蛋白质的非活性，N末端截断版本。我们建议小型同工型调节 通过抑制全长RECA的活性，MGPBC/MGPAR重组。此外，我们已经确定 这种新型功能的新蛋白质可减少抗原和相变。我们假设这是 推定的膜蛋白控制MGPBC/MGPAR重组，以响应环境信号。在 此外，我们确定低二氧化碳的增长会增强抗原和相变率。建筑 在这些初步发现中，我们寻求资金来探索全长的截短同工型的功能 RECA活性（AIM 1），定义了我们新的抗原和相位变化的机制 确定的膜蛋白，包括其相互作用伙伴的推定网络（AIM 2），并探索如何 二氧化碳和其他环境条件会影响这一过程（AIM 3）。最后，我们将研究 这些关于重组基因转录和RECA同工型表达的条件，从而定义 控制该生物体中MGPBC/MGPAR重组的途径。我们预计这项研究将会 揭示一种新颖，复杂且严格调节的抗原和相变的系统，介导生存和 在临床意义且极其挑剔的病原体中逃避宿主免疫反应。