DNA Repair Mechanisms in Candida albicans

白色念珠菌的 DNA 修复机制

• 批准号: 6833466
• 负责人: Richard Arthur Calderone
• 金额: $ 30.95万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2006-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6833466
• 关键词: DNA; Repair; Mechanisms; Candida; albicans

EXCEED THE SPACE PROVIDED. DNA repair in the human pathogen Candida albicans has not been studied to any great extent in spite of numerous observations that suggest extensive genomic variability among isolates. It is likely that this variability is a reflection of a variety of genomic alterations that include, deletions, translocations, ploidy changes, as well as loss of chromosomes or parts of chromosomes. The consequence of several of these processes has not been determined, but aneuploidy in this organism has been associated with the utilization of a carbohydrate as well as drug resistance. Homologous recombination [HR] and non-homologous end- joining [NHEJ] should be important components in DNA repair as a consequence of these genomic alterations. Beyond the role of these pathways in DNA repair, we have shown that strains of C. albicans deleted of LIG4 [NHEJ pathway] or RAD52 [HR pathway] have different growth phenotypes in that the lig 4 mutant is unable to form hyphae while the rad52 mutant forms filaments constitutively [i.e., even under non- inducing conditions]. These two observations indicate that DNA repair either directly or indirectly provides important functions in the morphogenesis of this organism. To understand the roles of these two DNA repair pathways in this organism, we propose four specific aims. Specific aim 1 includes the construction of new mutants in each of these two pathways. Lig4 and rad52 mutants have been constructed but others are needed to identify gene functions. In specific aim 2, proteins that interact with Lig4p will be identified. It is clear from the literature that the interacting proteins are different from those described for the Lig4p of S. cerevisiae. Microarray analysis will also be used to identify genes whose expression is regulated by Lig4p Specific aim 3 focuses upon the role of the HR and NHEJ proteins in DNA repair and morphogenesis, while specific aim 4 explores the relationship of candidate genes with virulence. In this regard, we have already published data that indicates a role for Lig4p in the virulence of C. albicans in an invasive model of candidiasis. We will now test this same mutant as well as the rad52 mutant in oral and vaginal candidiasis. The outcome of these studies will not only be the identification of proteins whose functions include DNA repair but also their role in morphogenesis. It is rather easy to believe that this unconventional human pathogen utilizes single pathways for multiple functions. PERFORMANCE SITE ========================================Section End===========================================

超出所提供的空间。人类病原体白色念珠菌中的DNA修复尚未在任何很大程度上进行研究，尽管许多观察表明分离株之间存在广泛的基因组变异性。这种变异性可能反映了多种基因组改变，包括缺失、易位、倍性变化以及染色体或部分染色体的丢失。这些过程中的几个的后果尚未确定，但在这种生物体的非整倍性已与碳水化合物的利用以及耐药性。同源重组[HR]和非同源末端连接[NHEJ]应该是DNA修复的重要组成部分，因为这些基因组改变。除了这些途径在DNA修复中的作用外，我们还发现C.缺失LIG4 [NHEJ途径]或RAD52 [HR途径]的白念珠菌具有不同的生长表型，其中LIG4突变体不能形成菌丝而rad52突变体组成型地形成丝状体[即，即使在非诱导条件下）。这两个观察结果表明，DNA修复直接或间接地提供了重要的功能，这种生物体的形态发生。为了了解这两种DNA修复途径在这种生物体中的作用，我们提出了四个具体的目标。具体目标1包括在这两个途径中的每一个中构建新的突变体。Lig4和rad52突变体已经构建，但需要其他突变体来鉴定基因功能。在具体目标2中，将鉴定与Lig4p相互作用的蛋白质。从文献中可以清楚地看出，相互作用的蛋白质与S的Lig4p所描述的蛋白质不同。啤酒。微阵列分析也将用于鉴定其表达受Lig4p调控的基因。特异性目标3侧重于HR和NHEJ蛋白在DNA修复和形态发生中的作用，而特异性目标4探索候选基因与毒力的关系。在这方面，我们已经发表的数据表明Lig4p在C.白色念珠菌在念珠菌病的侵袭性模型中。我们现在将在口腔和阴道念珠菌病中测试相同的突变体以及rad52突变体。这些研究的结果将不仅是鉴定其功能包括DNA修复的蛋白质，还包括它们在形态发生中的作用。很容易相信这种非常规的人类病原体利用单一途径实现多种功能。性能现场=