RATIONALE Longitudinal studies are required to distinguish within versus between-individual variation and repeatability of gene expression. They are uniquely positioned to decipher genetic signal from environmental noise, with potential application to gene variant and expression studies. However, longitudinal analyses of gene expression in healthy individuals-especially with regards to alternative splicing-are lacking for most primary cell types, including platelets. OBJECTIVE To assess repeatability of gene expression and splicing in platelets and use repeatability to identify novel platelet expression quantitative trait loci (QTLs) and splice QTLs. METHODS AND RESULTS We sequenced the transcriptome of platelets isolated repeatedly up to 4 years from healthy individuals. We examined within and between individual variation and repeatability of platelet RNA expression and exon skipping, a readily measured alternative splicing event. We find that platelet gene expression is generally stable between and within-individuals over time-with the exception of a subset of genes enriched for the inflammation gene ontology. We show an enrichment among repeatable genes for associations with heritable traits, including known and novel platelet expression QTLs. Several exon skipping events were also highly repeatable, suggesting heritable patterns of splicing in platelets. One of the most repeatable was exon 14 skipping of SELP. Accordingly, we identify rs6128 as a platelet splice QTL and define an rs6128-dependent association between SELP exon 14 skipping and race. In vitro experiments demonstrate that this single nucleotide variant directly affects exon 14 skipping and changes the ratio of transmembrane versus soluble P-selectin protein production. CONCLUSIONS We conclude that the platelet transcriptome is generally stable over 4 years. We demonstrate the use of repeatability of gene expression and splicing to identify novel platelet expression QTLs and splice QTLs. rs6128 is a platelet splice QTL that alters SELP exon 14 skipping and soluble versus transmembrane P-selectin protein production.

中文翻译：

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人类血小板中基因表达和剪接重复性的纵向 RNA-Seq 分析确定了血小板 SELP 剪接 QTL。

基本原理 需要纵向研究来区分基因表达的个体内部与个体之间的变异和可重复性。它们具有独特的优势，可以从环境噪声中破译遗传信号，并有可能应用于基因变异和表达研究。然而，对于包括血小板在内的大多数原代细胞类型，缺乏对健康个体基因表达的纵向分析——尤其是关于可变剪接的。目的评估血小板中基因表达和剪接的重复性，并利用可重复性来鉴定新的血小板表达数量性状基因座（QTL）和剪接QTL。方法和结果 我们对从健康个体中重复分离长达 4 年的血小板转录组进行了测序。我们检查了血小板 RNA 表达和外显子跳跃的个体变异和可重复性内部和之间，这是一种容易测量的替代剪接事件。我们发现血小板基因表达在个体之间和个体内部随着时间的推移通常是稳定的——除了富含炎症基因本体的基因子集。我们展示了与遗传性状相关的可重复基因的富集，包括已知和新的血小板表达 QTL。几个外显子跳跃事件也是高度可重复的，表明血小板剪接的遗传模式。最可重复的之一是外显子 14 跳过 SELP。因此，我们将 rs6128 鉴定为血小板剪接 QTL，并定义了 SELP 外显子 14 跳跃和种族之间的 rs6128 依赖性关联。体外实验表明，这种单核苷酸变体直接影响外显子 14 跳跃并改变跨膜与可溶性 P-选择素蛋白产生的比率。结论 我们得出结论，血小板转录组在 4 年内通常是稳定的。我们证明了使用基因表达和剪接的可重复性来识别新的血小板表达 QTL 和剪接 QTL。rs6128 是一种血小板剪接 QTL，它改变 SELP 外显子 14 跳跃和可溶性与跨膜 P-选择素蛋白的产生。我们证明了使用基因表达和剪接的可重复性来识别新的血小板表达 QTL 和剪接 QTL。rs6128 是一种血小板剪接 QTL，它改变 SELP 外显子 14 跳跃和可溶性与跨膜 P-选择素蛋白的产生。我们证明了使用基因表达和剪接的可重复性来识别新的血小板表达 QTL 和剪接 QTL。rs6128 是一种血小板剪接 QTL，它改变 SELP 外显子 14 跳跃和可溶性与跨膜 P-选择素蛋白的产生。