Consistent and contrasting properties of lineage-specific genes in the apicomplexan parasites Plasmodium and Theileria.
Consistent and contrasting properties of lineage-specific genes in the apicomplexan parasites Plasmodium and Theileria.
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DOI：
10.1186/1471-2148-8-108
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发表时间：
2008-04-11
影响因子：
3.4
通讯作者：
Kissinger, Jessica C.
中科院分区：
文献类型：
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作者：
Kuo, Chih-Horng;Kissinger, Jessica C.
谱系特异性基因，即仅限于相关生物的有限子集的基因，在适应中可能是重要的。在寄生生物体中，当宿主基因组中不存在谱系特异性基因产物时，这些基因产物是疫苗开发或治疗的可能靶点。在这项研究中，我们利用比较方法的基础上的系统发育框架来表征谱系特异性基因的寄生原生动物门Apicomplexa。两个主要的apicomplexan属，疟原虫和泰勒虫属，物种的基因，分为六个层次的谱系特异性的基础上的九个物种的同源性。在这两个属中，谱系特异性基因往往有较高水平的姐妹物种之间的序列分歧。此外，与基因组中的其他基因相比，物种特异性基因具有强烈的密码子使用偏好。我们发现，大量的属或种特异性基因是推定的表面抗原，可能参与宿主-寄生虫相互作用。有趣的是，这两种寄生虫谱系表现出几个显著的差异。在疟原虫中，第三密码子位置的（G + C）含量随着谱系特异性而增加，而泰勒虫则表现出相反的趋势。疟原虫的表面抗原具有种特异性，主要位于亚端粒区。与此相反，泰勒虫的表面抗原在属水平上是保守的，分布在整个染色体长度上。我们的研究结果提供了进一步的支持模型，即基因复制，然后迅速分歧是一个主要的机制，产生谱系特异性基因。许多谱系特异性基因是假定的表面抗原的结果支持谱系特异性基因在寄生虫适应中可能是重要的假设。在两个主要apicomplexan属的谱系特异性基因之间的对比特性表明，产生谱系特异性基因的机制和随后的进化命运可以在相关的寄生虫谱系之间不同。未来的研究，重点是提高寄生虫基因组的功能注释和收集的遗传变异数据在物种内和物种间的水平将是重要的，以促进我们的理解寄生虫的适应和自然选择。
Lineage-specific genes, the genes that are restricted to a limited subset of related organisms, may be important in adaptation. In parasitic organisms, lineage-specific gene products are possible targets for vaccine development or therapeutics when these genes are absent from the host genome. In this study, we utilized comparative approaches based on a phylogenetic framework to characterize lineage-specific genes in the parasitic protozoan phylum Apicomplexa. Genes from species in two major apicomplexan genera, Plasmodium and Theileria, were categorized into six levels of lineage specificity based on a nine-species phylogeny. In both genera, lineage-specific genes tend to have a higher level of sequence divergence among sister species. In addition, species-specific genes possess a strong codon usage bias compared to other genes in the genome. We found that a large number of genus- or species-specific genes are putative surface antigens that may be involved in host-parasite interactions. Interestingly, the two parasite lineages exhibit several notable differences. In Plasmodium, the (G + C) content at the third codon position increases with lineage specificity while Theileria shows the opposite trend. Surface antigens in Plasmodium are species-specific and mainly located in sub-telomeric regions. In contrast, surface antigens in Theileria are conserved at the genus level and distributed across the entire lengths of chromosomes. Our results provide further support for the model that gene duplication followed by rapid divergence is a major mechanism for generating lineage-specific genes. The result that many lineage-specific genes are putative surface antigens supports the hypothesis that lineage-specific genes could be important in parasite adaptation. The contrasting properties between the lineage-specific genes in two major apicomplexan genera indicate that the mechanisms of generating lineage-specific genes and the subsequent evolutionary fates can differ between related parasite lineages. Future studies that focus on improving functional annotation of parasite genomes and collection of genetic variation data at within- and between-species levels will be important in facilitating our understanding of parasite adaptation and natural selection.
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影响因子：
10.7
作者：
Castresana, J
通讯作者：
Castresana, J
影响因子：
64.8
作者：
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通讯作者：
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64.8
作者：
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通讯作者：
Wincker, Patrick
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影响因子：
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