MOLECULAR BIOLOGY OF CRYPTOCOCCUS NEOFORMANS

新型隐球菌的分子生物学

• 批准号: 3144050
• 负责人: JEFFREY C EDMAN
• 金额: $ 15.03万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-07-01 至 1995-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3144050
• 关键词: Cryptococcus neoformans; biological signal transduction; cell capsule; cell transformation; cryptococcosis; fungal genetics; genetic manipulation; microorganism genetics; molecular biology; mutant; pheromone; receptor; virulence

C. neoformans is the cause of 10% of all opportunistic infections in patients with AIDS. Therapy in these patients is complicated by the poor response rate, the need for chronic suppressive therapy, and intolerance to 5-fluorocytosine. Alternative and less toxic therapies would considerably enhance our ability to treat this disease. The proposed studies will begin with what is known of the genetics and biology of C. neoformans and begin to apply molecular biological techniques to address three areas of C. neoformans biology and pathobiology. Appreciation for the mechanisms of genetic control is paramount for the understanding of virulence in C. neoformans. One of our long-term goals is the dissection of the factors responsible for virulence in C. neoformans. In order to begin to understand these controls, we have developed a transformation system for C. neoformans. This allows for the first time the introduction of exogenous DNA into this pathogen. The current transformation system is not ideal as it appears to lack a true ARS and centromeric sequences. The proposed studies will seek these functions and should result in the production of vectors for the stable transformation of C. neoformans. Virulence in C. neoformans is associated with the ability to grow at 37degreesC, phenoloxidase activity, and the presence of capsule. The genes responsible for the production of capsule will be isolated by complementation of acapsular mutants. The phenoloxidase gene will be identified by its ability to form pigment on DOPA media. The genetic changes that underlie the formation of the sexual state are presumably initiated by secreted pheromones. The presence of these messengers will be tested by assessing morphologic and metabolic changes in response to extracts of opposite mating types. Genes for the pheromones and other sex-specific genes will be isolated by differential hybridization and the isolation of sterile mutants of C. neoformans. As sex pheromones result in G1 arrest of susceptible cells, they may provide novel targets for anticryptococcal therapy. Characterization of the pheromone receptors may eventually allow dissection of the signal transduction system in C. neoformans, which again may provide a therapeutic target. Even in the case that the pheromone-receptor axis is not a viable chemotherapeutic target, isolation of these genes and study of their control will be provide valuable insights into the gene regulation of C. neoformans.

在所有机会性感染中，有10%是由新生芽孢杆菌引起的 艾滋病患者。这些患者的治疗因穷人而变得复杂。 应答率、慢性抑制疗法的必要性以及对 5-氟胞嘧啶。毒性较小的替代疗法将大大 提高我们治疗这种疾病的能力。 拟议的研究将从已知的遗传学和 新生隐孢子虫的生物学，并开始应用分子生物学技术 以解决新生葡萄球菌生物学和病理生物学的三个领域。 对基因控制机制的理解对 对新生葡萄球菌毒力的了解。我们的长期目标之一是 对导致新生梭菌毒力的因素的剖析。 为了开始理解这些控制，我们开发了一个 新生隐孢子菌的转化体系。这是第一次允许 将外源DNA导入这种病原体。海流 转型系统并不理想，因为它似乎缺乏真正的ARS和 着丝粒序列。拟议的研究将寻求这些功能和 应导致产生用于稳定转化的载体 新生革兰氏菌。 新生葡萄球菌的毒力与其生长能力有关 37℃，酚氧化酶活性，有无胶囊化。基因 负责生产胶囊剂的人员将被隔离 无囊化突变体的互补作用。酚氧化酶基因将是 通过其在DOPA介质上形成色素的能力进行鉴定。 性状态形成背后的基因变化是 可能是由分泌的信息素引发的。这些东西的存在 信使将通过评估形态和代谢变化进行测试 对相反交配类型的提取物的反应。信息素的基因 而其他性别特异的基因将通过差异杂交来分离 以及新生隐孢子虫无菌突变株的分离。作为性信息素 导致敏感细胞G1期停滞，它们可能提供新的靶点 用于抗隐球菌治疗。信息素受体的特性 可能最终允许在C语言中剖析信号转导系统。 新生杆菌，这可能再次提供一个治疗靶点。即使在这种情况下 信息素受体轴不是一个可行的化疗靶点， 将提供这些基因分离和它们的控制研究 对新生葡萄球菌基因调控的有价值的见解。