Chromosome loss in the fungal pathogen C. albicans

真菌病原体白色念珠菌的染色体丢失

基本信息

批准号：
7204157
负责人：
ALEXANDER D JOHNSON
金额：
$ 17.59万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
依托单位国家：
美国
项目类别：
财政年份：
2004
资助国家：
美国
起止时间：
2004-03-15 至 2009-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7204157
关键词：
Address Alleles Aneuploidy Antibodies Candida Candida albicans Cell division Cells Cellular Morphology Chromosome Breakage Chromosomes Complement Condition DNA DNA Probes Defect Diploid Cells Diploidy Environment Event Exhibits Facility Construction Funding Category Fluorescent in Situ Hybridization G2/M Arrest Generations Genes Genetic Recombination Genetic Transcription Genome Goals Growth Haploidy Homologous Gene Immunocompromised Host Infection Laboratories Lead Life Cycle Stages Maps Mating Types Meiosis Methods Microscopy Mitosis Mitotic Chromosome Mitotic Spindle Apparatus Modeling Molecular Genetics Numbers Oligonucleotides Organ Organism Partner in relationship Pathway interactions Pattern Physical Chromosome Mapping Play Ploidies Population Principal Investigator Research Personnel Role Sampling Serum Spottings Systemic infection Techniques Testing Thinking Time Tissues Virulence asexual base chromosome loss genetic analysis genetic manipulation in vivo insight mouse model pathogen programs research study response segregation tool

项目摘要

DESCRIPTION (provided by applicant): Candida albicans is the most common fungal pathogen, causing both mucosal and systemic infections, particularly in immunocompromised people. Until recently, this opportunistic pathogen was thought to be asexual, existing only as a diploid organism. However, a mating-type-like (MTL) locus was identified and genetic manipulation of it led to the laboratory construction of mating-competent strains of C. albicans. The products of mating are tetraploid strains that must undergo a reductional division to return to the diploid state if a complete sexual cycle is to be achieved. In C. albicans, this reductional division (from tetraploid to diploid) can occur by a non-meiotic mechanism involving concerted chromosome loss. The resultant diploids are themselves mating-competent, thereby completing a parasexual cycle in this organism. The goal of this study is to determine the mechanism of concerted chromosome loss in C. albicans, and to understand the role it plays in the life-cycle of the organism, with special emphasis on its possible role during infection. The pattern of chromosome loss from tetraploid strains will be mapped by taking intermediates in chromosome loss and hybridizing their DNA to Candida microarrays. This will reveal if certain chromosomes are lost preferentially, and whether they are lost in a prescribed order. Chromosome loss will also be examined by directly visualizing cells undergoing chromosome loss by microscopy. If chromosome non-disjunction is occurring then defects in the mitotic apparatus may be observed. The transcriptional profiles of diploid and tetraploid strains will also be compared. Particular emphasis will be placed on understanding the transcriptional program of tetraploid strains during chromosome loss. A major goal of these studies is to examine the role of the tetraploid and chromosome loss in infection. Therefore, the virulence of the tetraploid strain of C. albicans will be compared to that of diploid strains, and chromosome loss will be followed in models of infection. Finally, these studies will directly address whether Candida contains recessive lethal alleles in its diploid genome by construction of an allelic microarray. This will also allow recombination events that take place during the parasexual cycle of C. albicans to be identified.

描述（由申请人提供）：白色念珠菌是最常见的真菌病原体，引起粘膜和全身感染，特别是在免疫功能低下的人群中。直到最近，这种机会性病原体还被认为是无性的，仅作为二倍体生物存在。然而，一个类交配型（MTL）基因座被鉴定出来，并且对其进行基因操作，从而在实验室构建了具有交配能力的白色念珠菌菌株。交配产物是四倍体菌株，如果要实现完整的性周期，则必须经历减数分裂以返回二倍体状态。在白色念珠菌中，这种减少分裂（从四倍体到二倍体）可以通过涉及协调染色体丢失的非减数分裂机制发生。由此产生的二倍体本身具有交配能力，从而在该生物体中完成一个准有性循环。本研究的目的是确定白色念珠菌染色体协同丢失的机制，并了解其在生物体生命周期中所发挥的作用，特别强调其在感染过程中可能发挥的作用。四倍体菌株的染色体丢失模式将通过获取染色体丢失的中间体并将其 DNA 与念珠菌微阵列杂交来绘制。这将揭示某些染色体是否优先丢失，以及它们是否按规定顺序丢失。染色体丢失也可以通过显微镜直接观察经历染色体丢失的细胞来检查。如果发生染色体不分离，则可能会观察到有丝分裂装置的缺陷。还将比较二倍体和四倍体菌株的转录谱。将特别强调了解四倍体菌株在染色体丢失期间的转录程序。这些研究的一个主要目标是检查四倍体和染色体丢失在感染中的作用。因此，将白色念珠菌四倍体菌株的毒力与二倍体菌株的毒力进行比较，并在感染模型中追踪染色体丢失。最后，这些研究将通过构建等位基因微阵列直接解决念珠菌在其二倍体基因组中是否含有隐性致死等位基因。这也将允许识别白色念珠菌准性周期期间发生的重组事件。