Comparative genomics of Pneumocystis carinii with other protists:: Implications for life style
Comparative genomics of Pneumocystis carinii with other protists:: Implications for life style
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DOI：
10.1111/j.1550-7408.2004.tb00158.x
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发表时间：
2004-01-01
影响因子：
2.2
通讯作者：
Cushion, MT
中科院分区：
文献类型：
--
作者：
Cushion, MT
分析了三个原生动物基因组的差异遗传特征，这些特征可能与生物对它们独特的生活方式的适应有关。微孢子虫，楔形脑孢子虫，一种专性的细胞内寄生虫；子囊菌，卡氏肺孢子虫，被认为是一种条件致病菌；以及酿酒酵母，一种表现出自由生活方式的模式生物，被用来比较基因组结构，繁殖策略，以及通过特征基因的存在预测的代谢能力。基因组大小、基因数量和代谢功能随着有机体对宿主的依赖程度变得更高而降低。与之相反，细胞生长和分裂相关基因的密度和百分比在楔形棘球藻基因组中显著增加。专属的生活方式与基因数量、基因组大小和代谢能力的减少有关，而自由生活方式与基因复制和基因组的大部分复制相一致。卡氏肺孢子虫的基因组特征和代谢能力通常介于其他两个原生生物基因组之间，但独特的特征，如单个rDNA基因座的存在，可能表明这些生物可能处于更加依赖宿主的过程中。
Three protistan genomes were analyzed for differential genetic traits that may be associated with biological adaptations to their unique life styles. The microsporidian, Encephalitozoon cuniculi, an obligate intracellular parasite; the ascomycetes, Pneumocystis carinii, considered an opportunistic pathogen; and Saccharomyces cerevisiae, a model organism exhibiting a free-living lifestyle, were used in comparisons of genomic architecture, reproductive strategies, and metabolic capacity predicted by the presence of Signature genes. Genome size, gene number, and metabolic function decreased as the organisms became more, dependent on their hosts. In contrast, gene density and the percentage of genes dedicated to cell growth and division were substantially increased in the genome of E. cuniculi. The obligate life style was associated with reductions in gene number, genome size, and reduced metabolic capacity while the free-living life style was coincident with gene duplications and duplication of large portions of the genome. The genomic characteristics and metabolic capacity of P. carinii were usually intermediate between those of the other two protistan genomes, but unique characteristics such as the presence of a single rDNA locus may indicate that these organisms could be in the process of becoming more host dependent.