INRA Toulouse, UBIA & Plateforme Bioinformatique, UR 875, Chemin de Borde Rouge, Auzeville BP 52627, 31326 Castanet-Tolosan, France.
BMC Plant Biol. 2010 Dec 20;10:283. doi: 10.1186/1471-2229-10-283.
Short interstitial telomere motifs (telo boxes) are short sequences identical to plant telomere repeat units. They are observed within the 5' region of several genes over-expressed in cycling cells. In synergy with various cis-acting elements, these motifs participate in the activation of expression. Here, we have analysed the distribution of telo boxes within Arabidopsis thaliana and Oryza sativa genomes and their association with genes involved in the biogenesis of the translational apparatus.
Our analysis showed that the distribution of the telo box (AAACCCTA) in different genomic regions of A. thaliana and O. sativa is not random. As is also the case for plant microsatellites, they are preferentially located in the 5' flanking regions of genes, mainly within the 5' UTR, and distributed as a gradient along the direction of transcription. As previously reported in Arabidopsis, a conserved topological association of telo boxes with site II or TEF cis-acting elements is observed in almost all promoters of genes encoding ribosomal proteins in O. sativa. Such a conserved promoter organization can be found in other genes involved in the biogenesis of the translational machinery including rRNA processing proteins and snoRNAs. Strikingly, the association of telo boxes with site II motifs or TEF boxes is conserved in promoters of genes harbouring snoRNA clusters nested within an intron as well as in the 5' flanking regions of non-intronic snoRNA genes. Thus, the search for associations between telo boxes and site II motifs or TEF box in plant genomes could provide a useful tool for characterizing new cryptic RNA pol II promoters.
The data reported in this work support the model previously proposed for the spreading of telo boxes within plant genomes and provide new insights into a putative process for the acquisition of microsatellites in plants. The association of telo boxes with site II or TEF cis-acting elements appears to be an essential feature of plant genes involved in the biogenesis of ribosomes and clearly indicates that most plant snoRNAs are RNA pol II products.
短的串联重复序列（telobox）是与植物端粒重复单位相同的短序列。它们存在于细胞周期中过度表达的几个基因的 5' 区域内。这些motif 与各种顺式作用元件协同作用，参与基因表达的激活。在这里，我们分析了 telobox 在拟南芥和水稻基因组中的分布及其与参与翻译装置生物发生的基因的关联。
我们的分析表明，telobox（AAACCCTA）在拟南芥和水稻不同基因组区域的分布不是随机的。与植物微卫星一样，它们优先位于基因的 5' 侧翼区域，主要位于 5'UTR 中，并沿着转录方向呈梯度分布。与之前在拟南芥中报道的情况一样，在水稻中编码核糖体蛋白的基因的几乎所有启动子中都观察到 telobox 与 site II 或 TEF 顺式作用元件的保守拓扑关联。这种保守的启动子组织可以在其他参与翻译机制生物发生的基因中找到，包括 rRNA 加工蛋白和 snoRNA。引人注目的是，telobox 与 site II 基序或 TEF 盒的关联在具有嵌套在内含子中的 snoRNA 簇的基因的启动子以及非内含子 snoRNA 基因的 5' 侧翼区域中是保守的。因此，在植物基因组中搜索 telobox 与 site II 基序或 TEF 盒之间的关联可以为鉴定新的隐匿 RNA pol II 启动子提供有用的工具。
本工作中报告的数据支持了先前提出的 telobox 在植物基因组中扩散的模型，并为植物中微卫星的获得提供了新的见解。telobox 与 site II 或 TEF 顺式作用元件的关联似乎是参与核糖体生物发生的植物基因的一个基本特征，并且清楚地表明大多数植物 snoRNA 是 RNA pol II 的产物。
