Extending the model of Arabidopsis telomere length and composition across Brassicaceae.
Extending the model of Arabidopsis telomere length and composition across Brassicaceae.
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将拟南芥端粒长度和组成模型扩展到十字花科。
DOI：
10.1007/s10577-014-9423-y
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Nelson AD
中科院分区：
文献类型：
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作者：
Nelson AD
端粒是一种重复的富含TG的DNA元件，在几乎所有的真核生物中对于维持基因组的稳定性和细胞的复制能力至关重要。关于植物端粒的大部分知识来自被子植物拟南芥，它已经成为端粒生物学的重要比较模型。拟南芥基因组可以承受许多损伤，其中许多损伤在其他真核系统如酵母和脊椎动物中是灾难性的或致命的。尽管拟南芥在建立植物端粒结构和调控模型方面具有重要意义，但只有少数研究使用这些信息来分析陆地植物的端粒组分，甚至是拟南芥在植物科中最接近的亲属。在这里，我们确定了如何以及拟南芥代表拟南芥科的端粒生物学的多个方面进行比较，在代表主要分支的物种在家谱。具体来说，我们确定了端粒重复序列，测量散装端粒长度，并分析了端粒长度的变化对同线染色体臂。此外，我们使用系统发育的方法来推断推定的端粒结合蛋白，CTC 1，STN1，TEN1（CST），端粒重复结合因子样（TRFL），和单一Myb组蛋白（SMH）的进化历史。我们的分析显示端粒DNA重复序列的保守性，但相当大的变化，端粒长度之间的采样物种，即使在同线染色体臂的比较。我们还发现，单链和双链端粒DNA结合复合物CST和TRFL，分别在其基因复制和丢失的模式不同。TRFL和SMH基因家族经历了许多重复事件，并且这些重复拷贝通常保留在基因组中。相比之下，CST组件发生在所有采样的基因组中的单拷贝基因，即使在物种经历了最近的全基因组复制事件。两者合计，我们的研究结果将拟南芥模型的背景下，其他物种在拟南芥科，使家庭的最佳特征植物组端粒结构方面。
Telomeres are repetitive TG-rich DNA elements essential for maintaining the stability of genomes and replicative capacity of cells in almost all eukaryotes. Most of what is known about telomeres in plants comes from the angiospermArabidopsis thaliana, which has become an important comparative model for telomere biology. Arabidopsis tolerates numerous insults to its genome, many of which are catastrophic or lethal in other eukaryotic systems such as yeast and vertebrates. Despite the importance of Arabidopsis in establishing a model for the structure and regulation of plant telomeres, only a handful of studies have used this information to assay components of telomeres from across land plants, or even among the closest relatives of Arabidopsis in the plant family Brassicaceae. Here, we determined how well Arabidopsis represents Brassicaceae by comparing multiple aspects of telomere biology in species that represent major clades in the family tree. Specifically, we determined the telomeric repeat sequence, measured bulk telomere length, and analyzed variation in telomere length on syntenic chromosome arms. In addition, we used a phylogenetic approach to infer the evolutionary history of putative telomere-binding proteins, CTC1, STN1, TEN1 (CST), telomere repeat-binding factor like (TRFL), and single Myb histone (SMH). Our analyses revealed conservation of the telomeric DNA repeat sequence, but considerable variation in telomere length among the sampled species, even in comparisons of syntenic chromosome arms. We also found that the single-stranded and double-stranded telomeric DNA-binding complexes CST and TRFL, respectively, differ in their pattern of gene duplication and loss. The TRFL and SMH gene families have undergone numerous duplication events, and these duplicate copies are often retained in the genome. In contrast, CST components occur as single-copy genes in all sampled genomes, even in species that experienced recent whole genome duplication events. Taken together, our results place the Arabidopsis model in the context of other species in Brassicaceae, making the family the best characterized plant group in regard to telomere architecture.