Centromere structure and isochromosome formation in Candida albicans

描述（由申请人提供）：白色念珠菌是最常见的人类真菌病原体，能够引起侵袭性念珠菌病，这是一种死亡率和医疗费用高的严重疾病。氟康唑是治疗念珠菌感染最常用的口服抗真菌药物，对氟康唑的获得性耐药（FluR）是一个重要问题。非整倍性，这是由非分离事件，涉及着丝粒，是强烈相关的FluR。C.白色念珠菌着丝粒的独特之处在于是区域性的，就像那些高等真核生物一样，但是附着于单个微管并且缺乏着丝粒周围的异染色质，就像酿酒酵母点着丝粒一样。对C.白色念珠菌着丝粒和动粒蛋白成分与他们将提供更好地了解CEN的结构和功能。这些知识可用于直接抗真菌药物的鉴定以及通过改变CEN功能来开发改变非整倍体频率和FluR获得的伴随药物。该项目将表征C.白色念珠菌动粒，集中在DASH蛋白复合物的成员。预测的同源物的DASH复合体成员在S。酿酒酵母和粟酒裂殖酵母将着丝粒附着到微管上。重要的是，DASH复合体蛋白在许多致病真菌中是保守的，并且在后生动物中缺乏同源物。In S. DASH复合物成员对于生长是必需的，并且可能是有希望的药物靶点。该提案解决了C中DASH复合体成员的本地化问题。DASH复合体成员与其他动粒蛋白的相互作用，以及DASH复合体成员对白色念珠菌的重要性。白色念珠菌生长此外，本计画亦将验证在某些C.白色念珠菌CEN区域有助于节段性非整倍性的发展，从而有助于获得耐药性。总之，拟议的实验将表征DASH复合蛋白作为潜在的抗真菌药物靶标，并深入了解节段性非整倍体形成的机制，这一过程与氟康唑耐药性的发展相关。公共卫生相关性：白色念珠菌是最常见的人类真菌病原体，其对治疗期间使用的抗真菌药物的耐药性是一个重要问题。这项提议将研究几种与C.白色念珠菌着丝粒，以表征其作为抗真菌药物靶标的潜力。此外，该项目将深入了解导致对常用抗真菌药物产生耐药性的特定染色体修复的机制。

DESCRIPTION (provided by applicant): Candida albicans is the most prevalent human fungal pathogen and is capable of causing invasive candidiasis, a severe disease with high mortality rates and medical costs. Fluconazole is the most frequently prescribed oral antifungal for treating Candida infections and acquired resistance to fluconazole (FluR) is a significant problem. Aneuploidies, which arise from non-disjunction events that involve centromeres, are strongly correlated with FluR. C. albicans centromeres are unique in being regional, like those of higher eukaryotes, yet attaching to a single microtubule and lacking pericentric heterochromatin, like Saccharomyces cerevisiae point centromeres. Characterization of C. albicans centromeres and the kinetochore protein components associated with them will provide a better understanding of CEN structure and function. This knowledge can be exploited for the identification of direct anti-fungal drugs as well as for the development of companion drugs that alter the frequency of aneuploidies and the acquisition of FluR,by altering CEN function. This project will characterize the structure of the C. albicans kinetochore, focusing on members of the DASH protein complex. Predicted homologs of DASH complex members in S. cerevisiae and Schizosaccharomyces pombe attach centromeres to microtubules. Importantly, DASH complex proteins are conserved in many pathogenic fungi and lack homologs in metazoans. In S. cerevisiae, DASH complex members are essential for growth and may be promising drug targets. This proposal addresses the localization of DASH complex members in C. albicans, the interactions between DASH complex members and other kinetochore proteins, and the essentiality of DASH complex members for C. albicans growth. In addition, this project will test the hypothesis that the inverted repeat DNA sequences found in some C. albicans CEN regions contribute to the development of segmental aneuploidies and thus to the acquisition of drug resistance. Together, the proposed experiments will characterize the DASH complex proteins as potential antifungal drug targets and gain insight into the mechanism of segmental aneuploidy formation, a process that is correlated with the development of resistance to fluconazole. PUBLIC HEALTH RELEVANCE: Resistance of Candida albicans, the most commonly isolated human fungal pathogen, to anti- fungal drugs used during treatment is a significant problem. This proposal will examine several proteins associated with the C. albicans centromere to characterize their potential as anti-fungal drug targets. Also, this project will gain insight into the mechanism of how specific chromosomal rearrangments that result in resistance to a commonly used anti-fungal drug arise.