Genome-wide mapping reveals single-origin chromosome replication in Leishmania, a eukaryotic microbe
Genome-wide mapping reveals single-origin chromosome replication in Leishmania, a eukaryotic microbe
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DOI：
10.1186/s13059-015-0788-9
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发表时间：
2015-10-19
期刊：
影响因子：
12.3
通讯作者：
McCulloch, Richard
中科院分区：
文献类型：
--
作者：
Marques, Catarina A.;Dickens, Nicholas J.;McCulloch, Richard
背景：DNA复制起始于定义的基因组位点，称为起点。起源的使用似乎遵循迄今为止所研究的真核生物的共同规则：所有染色体都是从多个起源复制的，这些起源显示出发射效率的变化，并且是从更大的潜在起源池中选择的。要问这些功能的DNA复制是真的所有真核生物，我们描述了全基因组的起源映射在寄生虫利什曼原虫。结果：起源映射利什曼原虫表明一个惊人的分歧，起源使用相对于特征的真核生物，因为每个染色体似乎是从一个单一的起源复制。通过比较两个物种的利什曼原虫，我们发现的证据表明，这种起源奇点是保持在面对染色体融合或裂变事件在进化过程中。绘制利什曼原虫的起源表明，所有的起源火具有相同的效率，并且起源所占据的基因组位点不同于相关的非起源位点。最后，我们提供的证据表明，在利什曼原虫的起源位置显示惊人的保护与布氏锥虫，尽管后者寄生虫复制其染色体从多个，可变强度的起源。利什曼原虫（一种微生物真核生物）染色体复制的单一起源的证明，对起源多样性和相关控制的进化具有意义，并可能解释普遍的非整倍体，利什曼原虫染色体结构的特点。
Background: DNA replication initiates on defined genome sites, termed origins. Origin usage appears to follow common rules in the eukaryotic organisms examined to date: all chromosomes are replicated from multiple origins, which display variations in firing efficiency and are selected from a larger pool of potential origins. To ask if these features of DNA replication are true of all eukaryotes, we describe genome-wide origin mapping in the parasite Leishmania.Results: Origin mapping in Leishmania suggests a striking divergence in origin usage relative to characterized eukaryotes, since each chromosome appears to be replicated from a single origin. By comparing two species of Leishmania, we find evidence that such origin singularity is maintained in the face of chromosome fusion or fission events during evolution. Mapping Leishmania origins suggests that all origins fire with equal efficiency, and that the genomic sites occupied by origins differ from related non-origins sites. Finally, we provide evidence that origin location in Leishmania displays striking conservation with Trypanosoma brucei, despite the latter parasite replicating its chromosomes from multiple, variable strength origins.Conclusions: The demonstration of chromosome replication for a single origin in Leishmania, a microbial eukaryote, has implications for the evolution of origin multiplicity and associated controls, and may explain the pervasive aneuploidy that characterizes Leishmania chromosome architecture.