MOLECULAR BIOLOGY OF CRYPTOCOCCUS NEOFORMANS

新型隐球菌的分子生物学

• 批准号: 2064907
• 负责人: JEFFREY C EDMAN
• 金额: $ 3.36万
• 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 1995-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2064907
• 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.

C.新生儿是10%的机会性感染的原因， 艾滋病患者。 这些患者的治疗因穷人而复杂化 反应率，对慢性抑制治疗的需要，以及对 5-氟胞嘧啶 替代和毒性较小的治疗方法将大大 增强我们治疗这种疾病的能力。 拟议的研究将开始与什么是已知的遗传学和 生物学C.新生儿和开始应用分子生物学技术 解决C. neoformans生物学和病理生物学。 对遗传控制机制的理解对人类的生存至关重要。 了解C.新人类 我们的长期目标之一是 对C.新人类 为了开始理解这些控件，我们开发了一个 转化系统C.新人类 这是第一次允许 将外源DNA引入这种病原体。 当前 转换系统并不理想，因为它似乎缺乏真正的ARS， 着丝粒序列 拟议的研究将寻求这些职能， 应导致产生载体，用于稳定转化 C.新人类 C.新生儿的生长速度与 37 ℃，酚氧化酶活性，和胶囊的存在。 的基因 负责生产胶囊的人将被隔离， 无囊突变体的互补。 酚氧化酶基因将 通过其在DOPA介质上形成颜料的能力来鉴定。 性状态形成的基因变化是 可能是由分泌的信息素引发的 存在这些 将通过评估信使的形态和代谢变化来测试信使 对相反交配类型的提取物的反应。 信息素的基因 和其他性别特异性基因将被分离的差异杂交 以及C.新人类 作为性信息素 导致敏感细胞的G1期阻滞，它们可能提供新的靶点 用于抗隐球菌治疗 信息素受体的表征 可能最终允许解剖C. 这也可能提供一个治疗靶点。 即使是 信息素受体轴不是可行的化疗靶点， 将提供这些基因分离及其控制的研究 对C.新人类