MOLECULAR GENETIC BASIS OF MYCOPLASMA ANTIGEN VARIATION

支原体抗原变异的分子遗传学基础

• 批准号: 3146706
• 负责人: KIM S. WISE
• 金额: $ 12.59万
• 依托单位: UNIVERSITY OF MISSOURI-COLUMBIA
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-08-01 至 1996-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3146706
• 关键词: Escherichia coli; Mycoplasma; bacterial DNA; bacterial cytopathogenic effect; chromosome walking; chromosomes; epitope mapping; gene expression; gene mutation; gene rearrangement; genetic mapping; genetic regulatory element; genetic strain; genetic transcription; membrane proteins; microorganism genetics; molecular genetics; monoclonal antibody; nonblood lipoprotein; nucleic acid probes; nucleic acid sequence; polymerase chain reaction; protein sequence; restriction fragment length polymorphism; surface antigens; transposon /insertion element

The long range objective of this project is to understand the molecular and genetic basis of systems providing pathogenic bacteria the heritable capability to generate phenotypic diversity. diversity-generating systems provide pathogens an enormous potential for adapting to and withstanding their respective host environments. Since these systems often involve the surface structures on unicellular microbes, characterization of new molecular motifs of surface phenotypic variation is important in understanding microbial strategies for adaptation. It is proposed to characterize a newly-discovered microbial system of antigenic variation involving novel surface structures. This occurs in Mycoplasma hyorhinis, a pathogenic mycoplasma of swine. Mycoplasmas comprise a large group of specially-adapted wall-less procaryotic organisms that cause or are associated with several diseases in animals, including man. They appear to be associated with respiratory, genitourinary and other human disorders, now including acquired immunodeficiency syndrome. Mycoplasma hyorhinis has been shown to undergo high-frequency phase variation in the expression of variable lipoprotein (Vlp) surface antigens. structurally distinct Vlp products display non-coordinate phase variation and reversible size variation in vitro. Biochemical data and sequencing of recently identified vlp genes revealed a novel periodic structure in the C- terminal extracellular region of these otherwise highly conserved membrane- anchored lipoproteins. It is proposed to examine the structural and molecular genetic basis for Vlp antigenic and phase variation in order to understand how this unique molecular adaptation may provide these specialized microbes with the capacity to generate extensive surface diversity. Investigating this system may enhance our global understanding of microbial strategies for environmental adaptation, and may reveal common strategies used by several human and animal mycoplasma pathogens. the vlp genes from isogenic M. hyorhinis populations with defined variations in Vlp structure, size or expression, will be physically mapped, sequenced and expressed in order to determine genomic organization, structural and antigenic features, divergence and rearrangements mediating antigenic or phase variation. Restriction mapping, cloning, sequencing and expression of genomic fragments will be used. Accessible surface regions of Vlp antigens will be mapped with monoclonal antibodies on mutationally altered recombinant Vlp products, and transcription of vlp genes will be assessed in isogenic variants by standard methods.

该项目的长期目标是了解分子和 为致病菌提供可遗传性的系统的遗传基础 产生表型多样性的能力。 多样性生成系统 为病原体提供巨大的适应和抵抗潜力 他们各自的宿主环境。 由于这些系统通常涉及 单细胞微生物的表面结构、新特征 表面表型变异的分子基序在 了解微生物的适应策略。 建议表征新发现的微生物系统 涉及新表面结构的抗原变异。 这发生在 猪鼻支原体，猪的一种致病性支原体。 支原体 包括一大群经过特殊改造的无壁原核生物 导致动物多种疾病或与之相关的疾病，包括 男人。 它们似乎与呼吸系统、泌尿生殖系统和 其他人类疾病，现在包括获得性免疫缺陷综合症。 猪鼻支原体已被证明经历高频阶段 可变脂蛋白（Vlp）表面抗原表达的变化。 结构不同的 Vlp 产品显示非坐标相位变化 和体外可逆的尺寸变化。 生化数据和测序 最近发现的 vlp 基因揭示了 C 中的一种新的周期性结构 这些高度保守的膜的末端细胞外区域 锚定脂蛋白。 建议审查结构和 Vlp 抗原和相位变异的分子遗传学基础，以便 了解这种独特的分子适应如何提供这些 能够产生大面积表面的特殊微生物 多样性。 研究这个系统可能会增强我们的全球理解 微生物适应环境的策略，并可能揭示常见的 几种人类和动物支原体病原体使用的策略。 极少数人 来自具有 Vlp 确定变异的等基因猪鼻支原体群体的基因 结构、大小或表达，将被物理映射、排序和 表达以确定基因组组织、结构和 抗原特征、介导抗原或抗原的分歧和重排 相位变化。 限制性图谱、克隆、测序和表达 将使用基因组片段。 Vlp 可到达的表面区域 抗原将用突变改变的单克隆抗体进行定位 将评估重组 Vlp 产品和 vlp 基因的转录 通过标准方法形成等基因变体。