Determinants of SINE mobilization in the domestic dog.

摘要 转座元件(TES)广泛存在于真核生物基因组中，是真核生物的重要调节因子。 基因组变异、表型和疾病。在人类和其他哺乳动物中，绝大多数TE家族 由于宿主内累积的突变而有缺陷，但其中一些仍然能够产生新的拷贝。 这些元件在细胞内的传播可导致零星疾病和通过插入突变或 通过非等位同源重组促进重排。了解诱变剂 特定TE系列提供的潜力需要对其谱系、单个副本和功能进行细化 影响宿主内部动员能力的属性。短长穿插元素(正弦 和品系)通过一种称为逆转录转座的细胞内“复制和粘贴”过程进行动员。正弦是非正弦的 通过从反向转位能力强的品系中招募运输职能来自主和动员， 部分是通过RNA中间体上的L1 ORF2蛋白(ORF2p)聚(A)-尾识别完成的。人类 Sine Alu来源于信号识别颗粒(SRP)的7SL RNA，它是一种细胞质 核糖核蛋白在共翻译靶向分泌途径时停靠在核糖体上的核糖核蛋白。这个 衍生的Alu以两个7SL‘Alu’单体串联存在；两者都保留了7SL的祖先结构和细胞质 结合伙伴SRP9/14，将Alu RNA引导到核糖体，然后在核糖体中转移L1 ORF2p进行自己的编码 MRNA.在其独特的起源上，tRNA祖先的SINES包括具有保守结构的年轻家族 在某些物种中高度动态化。这些观察和我们自己的发现使我们假设 Trna氨基酸中间体的动员是通过与进化保守的细胞结合来实现的。 与ALU相似但在生物学上截然不同的模型中的因素。我们之前检测了一个可移动的~180bp的正弦 狗的tRNALys祖先，SINCEC_CF，表现出高度的多态，序列 保护，以及与疾病和人工选择的表型相关的插入。我们已经证明了这一点 真L1Cf驱动的顺式转座和反式合成SINCEC_CF共识 与观察到的Alu/L1Hs相比，被认为是“热门”的比率。此外，天然的动员分析 出现的SINCEC_CF变体暴露了直接影响共识初级序列的变化 动员。我们利用这个模型来解决我们的假设，并确定所需的结构性因素 使用基因组、生化、分子和遗传学的组合来动员tRNA Sine 实验方法。这一建议将为犬体内的氨基酸动员特性提供基础。 应用于人类健康的比较基因组分析的模型和变异资源。

Abstract Transposable elements (TEs) have abundantly colonized eukaryotic genomes and are profound mediators of genomic variation, phenotypes, and disease. In humans and other mammals, the vast majority of TE families are defective due to accumulated mutations within the host, but some remain capable of generating new copies. Intracellular spread of such elements can lead to sporadic disease and variation via insertional mutagenesis or by facilitating rearrangements through non-allelic homologous recombination. Understanding the mutagenic potential offered from a particular TE family requires refinement of its lineages, individual copies, and functional properties that affect mobilization capacities within the host. The short and long interspersed elements (SINEs and LINEs) mobilize through an intracellular ‘copy and paste’ process termed retrotransposition. SINEs are non- autonomous and mobilize by recruiting functions in trans from a retrotransposition-competent LINE, accomplished in part by L1 ORF2 protein (ORF2p) poly(A)-tail recognition on the RNA intermediate. The human SINE Alu originated ~65 mya from the 7SL RNA of signal recognition particle (SRP), a cytoplasmic ribonucleoprotein that docks on the ribosome during co-translational targeting to the secretory pathway. The derived Alu exists as two 7SL ‘Alu’ monomers in tandem; both retain 7SL ancestral structure and cytoplasmic binding partners SRP9/14 that direct Alu RNA to ribosome, where it then diverts L1 ORF2p for its own encoding mRNA. Distinct in their origin, SINEs of tRNA ancestry include young families of conserved structure that are highly mobilized in some species. These observations and our own findings lead us to hypothesize that mobilization of the tRNA SINE intermediate is achieved by association with evolutionarily conserved cellular factors in a similar but biologically distinct model to that of Alu. We previously examined a mobile ~180bp SINE of tRNALys ancestry from the canine, SINCEC_Cf, that exhibits high levels of polymorphism, sequence conservation, and insertions linked to disease and artificially selected phenotypes. We have demonstrated bona fide L1Cf-driven retrotransposition of its own mRNA in cis and a synthetic SINCEC_Cf consensus in trans at rates considered ‘hot’ in comparison to those observed for Alu/L1Hs. Moreover, mobilization assays of naturally occurring SINCEC_Cf variants expose alterations to the consensus primary sequence that directly affect mobilization. We take advantage of this model to address our hypothesis and identify structural factors required for mobilization of the tRNA SINE using a combination of genomic, biochemical, molecular, and genetic experimental approaches. This proposal will provide the foundation for SINE mobilization properties in the canine model and a variant resource for comparative genomic analysis in application to human health.