MicroRNA Sequence Variation Potentially Contributes to Within-Species Functional Divergence in the Nematode Caenorhabditis briggsae
MicroRNA Sequence Variation Potentially Contributes to Within-Species Functional Divergence in the Nematode Caenorhabditis briggsae
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DOI：
10.1534/genetics.111.132795
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发表时间：
2011-11-01
期刊：
影响因子：
3.3
通讯作者：
Cutter, Asher D.
中科院分区：
文献类型：
--
作者：
Jovelin, Richard;Cutter, Asher D.
越来越多的证据表明基因调控的差异是表型变异的主要来源。 MicroRNA介导的转录后调控最近已成为发育过程中控制基因活性的关键因素。 MicroRNA 基因在基因组中含量丰富，通过指导翻译抑制来充当基因表达的管理者。因此，了解群体内 microRNA 序列变异的作用对于充分剖析自然界表型多样性的起源和维持至关重要。在这项研究中，我们研究了线虫 Caenorhabditis briggsae（秀丽隐杆线虫的近亲）中 microRNA 位点的等位基因变异。 C. briggsae 的系统发育地理学结构将全球大多数菌株划分为“温带”或“热带”分支，其中少数菌株具有不同的、受地理限制的基因型。值得注意的是，遵循这种纬度二分法的菌株在与温度相关的适应性方面也有所不同。考虑到这种系统发育地理学模式，我们检查了 C. briggsae 分离株的全球样本中 18 个 miRNA 的多态性，并测试了新分离的菌株是否符合这种系统发育地理学。令人惊讶的是，这类通常经历强烈纯化选择的基因的核苷酸多样性相对较高。特别是，我们发现 C. briggsae 中的 miRNA 比拟南芥中的 miRNA 具有更多的多态性，尽管两个物种之间的中性位点多样性背景水平相似。我们发现，一些突变表明基于目标位点识别的要求和多态性对 RNA 折叠影响的计算预测的功能分歧。这些发现表明 miRNA 多态性有可能导致物种内表型变异。序列以登录号保存在 GenBank 中。 JN251323-JN251744。
Mounting evidence points to differences in gene regulation as a major source of phenotypic variation. MicroRNA-mediated post-transcriptional regulation has emerged recently as a key factor controlling gene activity during development. MicroRNA genes are abundant in genomes, acting as managers of gene expression by directing translational repression. Thus, understanding the role of microRNA sequence variation within populations is essential for fully dissecting the origin and maintenance of phenotypic diversity in nature. In this study, we investigate allelic variation at microRNA loci in the nematode Caenorhabditis briggsae, a close relative of C. elegans. Phylogeographic structure in C. briggsae partitions most strains from around the globe into a "temperate" or a "tropical" clade, with a few strains having divergent, geographically restricted genotypes. Remarkably, strains that follow this latitudinal dichotomy also differ in temperature-associated fitness. With this phylogeographic pattern in mind, we examined polymorphisms in 18 miRNAs in a global sample of C. briggsae isolates and tested whether newly isolated strains conform to this phylogeography. Surprisingly, nucleotide diversity is relatively high in this class of gene that generally experiences strong purifying selection. In particular, we find that miRNAs in C. briggsae are substantially more polymorphic than in Arabidopsis thaliana, despite similar background levels of neutral site diversity between the two species. We find that some mutations suggest functional divergence on the basis of requirements for target site recognition and computational prediction of the effects of the polymorphisms on RNA folding. These findings demonstrate the potential for miRNA polymorphisms to contribute to phenotypic variation within a species. Sequences were deposited in GenBank under accession nos. JN251323-JN251744.