Evolution of resistance to scorpion neurotoxins

蝎子神经毒素抵抗力的进化

• 批准号: 7114116
• 负责人: ASHLEE Hedgecock ROWE
• 金额: $ 4.6万
• 依托单位: UNIVERSITY OF TEXAS AT AUSTIN
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-20 至 2009-04-19
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7114116
• 关键词: Arachnida; Rodentias; arthropod poison; binding proteins; detoxification; evolution; field study; genetic polymorphism; genetic susceptibility; neurotoxins; postdoctoral investigator; potassium channel; protein structure function; receptor sensitivity; sodium channel; species difference; voltage gated channel

DESCRIPTION (provided by applicant): The Arizona bark scorpion (Centruroides exilicauda) and the striped bark scorpion (C. vittatus) produce neurotoxins that selectively bind voltage-gated ion channels in excitable membranes of nerve and muscle, producing hyper-excitability of the nervous and neuromuscular systems. Southern grasshopper mice (Onychomys torridus) and Mearns' grasshopper mice (O. arenicola) are voracious predators of scorpions in U.S. deserts. Southern and Mearns' grasshopper mice demonstrate physiological resistance to bark scorpion venom. Variability in venom resistance among grasshopper mice populations co-varies with geographic patterns of bark scorpion sympatry and allopatry. Electrophysiological assays show that ion channels in the nerve and muscle of grasshopper mice are insensitive to scorpion neurotoxins. The purpose of the proposed project is to determine the molecular genetic basis of ion channel insensitivity in resistant mice, to characterize the molecular variation underlying phenotypic differences in resistance levels among their populations, and to assess patterns of selection on genes involved in toxin resistance. Ion channel encoding genes will be examined for structural and functional changes that impart insensitivity to toxins.

描述（由申请人提供）：亚利桑那州树皮蝎子（Centruroides Exilicauda）和条纹树皮蝎子（C. vittatus）产生神经毒素，可在神经和肌肉激发膜上有选择地结合电压门控离子通道，从而产生神经和神经系统的高度效果。南部蚱hopper小鼠（洋葱托犬）和米恩斯的蚱hopper小鼠（O.竞技场）是美国沙漠中蝎子的狂热捕食者。南部和米恩斯的蚱hop小鼠表现出对树皮蝎子毒液的生理抗药性。蚱hopper小鼠种群中毒性耐药性的变异性与树皮蝎子的地理模式和异形。电生理测定表明，蚱hop小鼠的神经和肌肉中的离子通道对蝎子神经毒素不敏感。拟议项目的目的是确定抗性小鼠离子通道不敏感性的分子遗传基础，以表征其种群中抗性水平的表型差异的分子变异，并评估毒性抗性涉及基因的选择模式。将检查编码基因的离子通道的结构和功能变化，这些变化对毒素施加了不敏感的情况。