Echinocandin resistant & hypersensitive C. albicans

描述（由申请人提供）：白色念珠菌是最常引起人类侵袭性疾病的真菌。这种感染具有严重后遗症和死亡的高风险，易受其感染的人数继续增加，与此同时，对损害患者免疫防御的严重疾病的治疗取得了进展。在这种真菌的血液感染中，归因死亡率接近40%。侵袭性念珠菌感染的高死亡率的一个原因是可用于其治疗的抗真菌药物的选择有限。棘白菌素是最近临床上可用的抗真菌药物的补充，具有几个重要的优点。为了保持棘白菌素在潜在的未来广泛使用期间的效用，早期鉴定引起棘白菌素抗性的突变将是有用的。棘白菌素的作用靶点是产生念珠菌细胞壁主要成分的酶。完整的壁对于真菌细胞的生存至关重要。在模式真菌酿酒酵母中，已经确定了许多调控细胞壁合成活性的调控回路。对棘白菌素具有抗性或过敏性的酵母突变体为分析这些调节回路提供了一个切入点。尽管从S.酿酒酵母、C.白色念珠菌显示出与酵母菌的重要区别，因为它已经进化到维持其细胞壁对抗宿主的免疫系统。我们提出了一个基因组调查的耐药性和过敏性棘白菌素在C。白色本身一组杂合子C.筛选白色念珠菌突变体在棘白菌素存在下的生长。使用转座子产生突变体，所述转座子仅使用二核苷酸作为识别序列以最大随机方式插入。通过我们在中试筛选中开发的方案，将收集抗性和过敏突变体。将确认它们的表型并鉴定转座子插入的位点。将通过在野生型菌株中的相同基因座中重建突变来确定转座子插入与棘白菌素相关表型的连锁。由此产生的念珠菌的棘白菌素反应所涉及的基因的概述将提供探针，以解剖网络，调节这种病原体的能力，以保持其细胞壁的完整性。

DESCRIPTION (provided by applicant): Candida albicans is the fungus most often causing invasive disease in humans. The number of susceptible individuals to this infection, which carries a high risk of serious sequelae and death, continues to rise, in parallel with the advances in treatment of serious illnesses that compromise patients' immune defenses. In bloodstream infections with this fungus, attributable mortality is close to 40%. One reason for the high mortality of invasive Candida infection is the limited choice of antifungal drugs available for its treatment. Echinocandins have been a recent addition to the clinically available antifungals, with several important advantages. In order to preserve the utility of the echinocandins during potential future widespread use, early identification of mutations which give rise to echinocandin resistance will be useful. The target of echinocandins is the enzyme that produces the major component of Candida's cell wall. An intact wall is critical for the fungal cell's survival. In the model fungus Saccharomyces cerevisiae, numerous regulatory circuits have been identified which govern the activity of cell wall synthesis. Saccharomyces mutants which are resistant or hypersensitive to echinocandins have provided an entry point for the analysis of these regulatory circuits. Though much can be learned from the insights gained in S. cerevisiae, the physiology and the genome of C. albicans show important differences from Saccharomyces, because it has evolved to maintain its cell wall against the host's immune system. We propose a genomic survey of resistance and hypersensitivity to echinocandins in C. albicans itself. A collection of heterozygous C. albicans mutants will be screened for their growth in the presence of an echinocandin. The mutants are generated using a transposon which inserts in a maximally random fashion, using only a dinucleotide as a recognition sequence. By a protocol we developed in a pilot screen, resistant and hypersensitive mutants will be collected. Their phenotypes will be confirmed and the locus of the transposon insertion will be identified. Linkage of the transposon insertion to the echinocandin-related phenotype will be determined by recreating a mutation in the same locus, in the wild type strain. The resulting overview of genes involved in Candida's echinocandin response will provide probes to dissect the networks that regulate this pathogen's ability to maintain the integrity of its cell wall.