MOLECULAR GENETIC BASIS OF MYCOPLASMA ANTIGEN VARIATION

描述(改编自申请人的摘要)：建议 研究多基因VLP(变量)的关键新适应特征 猪鼻支原体的脂蛋白)系统 在过去的资助期内的初步分子表征。这个系统 可变表面脂蛋白(VLP)是一种很有指导意义的很发达的 研究自适应遗传策略的模型和基本表面涂层 几种对人类有贡献的无壁支原体的特性 和动物疾病。VLP系统产生非坐标、高频 主面的表达方式和结构特征的转换 猪鼻分枝杆菌外壳脂蛋白的基因内突变 独立影响转录(VLP阶段变化)，或长度 不同VLP基因的3‘重复编码区(VLP大小变异) 聚集在染色体上。VLP中的结构变异和组合变异 在独特的单一质膜表面上表达的轮廓可以 深刻影响支原体的宿主内适应能力，包括 它们对宿主抗体的敏感性指向重要的表面结构。 具体目标将解决对此认识上的重大差距。 原型系统，包括：(I)自然变化的范围 VLP基因谱系，(II)VLP的程度、模式和后果 已建立的猪鼻分枝杆菌诱导关节炎模型的变异 天然猪宿主，以及(III)宿主抗体与VLP相互作用的性质 和其他表面蛋白，包括VLP在表面的可能作用 蒙面。方法包括基于聚合酶链式反应的VLP基因家族特征 在一系列初级分离株中，评估了生物的VLP图谱 原位或从动物宿主分离(通过免疫显微镜、聚合酶链式反应和 免疫化学技术)，并分析抗体与支原体的相互作用 类似的方法。预计这些努力将揭示重要战略。 一般适用于病原性支原体的适应性表面变异 以及其他使用遗传变异作为生存策略的微生物。

DESCRIPTION (Adapted from the applicant's abstract): It is proposed to examine critical new adaptive features of the multigene vlp (variable lipoprotein) system of Mycoplasma hyorhinis that were revealed during its initial molecular characterization in the past funding period. This system of variable surface lipoproteins (Vlps) is an instructive and well developed model for studying adaptive genetic strategies, and fundamental surface coat properties, of several wall-less mycoplasma species contributing to human and animal disease. The Vlp system produces non-coordinate, high frequency switching in the expression and in structural features of the major surface coat lipoproteins of M. hyorhinis, through intragenic mutations that independently affect transcription (Vlp phase variation), or the length of 3' repetitive coding regions (Vlp size variation) of divergent vlp genes clustered in the chromosome. Structural and combinatorial variation in Vlp profiles expressed on the unique single plasma membrane surface, may profoundly affect in-host adaptive capabilities of mycoplasmas, including their susceptibility to host Abs directed toward vital surface structures. Specific aims will address important gaps in the understanding of this prototype system, including: (i) the range of variation in the natural repertoire of vlp genes, (ii) the degree, pattern and consequences of Vlp variation in an established model of M. hyorhinis-induced arthritis in the natural swine host, and (iii) the nature of host Ab interactions with Vlps and other surface proteins, including the possible role of Vlps in surface masking. Approaches include PCR-based characterization of vlp gene families in a series of primary isolates, assessment of Vlp profiles of organisms in situ or isolated from the animal host (by immunomicroscopy, PCR and immunochemical techniques), and analysis of Ab-mycoplasma interactions by similar methods. These efforts are expected to reveal important strategies of adaptive surface variation generally applicable to pathogenic mycoplasmas and to other microbes employing genetic variation as a survival strategy.