Gene expression profiles in Norad+/+ and Norad-/- brains and spleens [RNA-seq]

Although numerous long noncoding RNAs (lncRNAs) have been identified, our understanding of their roles in mammalian physiology remains limited. Here we investigated the physiologic function of the conserved lncRNA Norad in vivo. Deletion of Norad in mice results in genomic instability and mitochondrial dysfunction, leading to a dramatic multi-system degenerative phenotype resembling premature aging. Loss of tissue homeostasis in Norad-deficient animals is attributable to augmented activity of PUMILIO proteins, which act as post-transcriptional repressors of target mRNAs to which they bind. Norad is the preferred RNA target of PUMILIO2 (PUM2) in mouse tissues and, upon loss of Norad, PUM2 hyperactively represses key genes required for mitosis and mitochondrial function. Accordingly, enforced Pum2 expression fully phenocopies Norad deletion, resulting in rapid-onset aging-associated phenotypes. These findings provide new insights and open new lines of investigation into the roles of noncoding RNAs and RNA binding proteins in normal physiology and aging. Gene expression profiles were determined by RNA-seq.尽管目前已鉴定出大量长链非编码RNA（long noncoding RNAs，lncRNAs），但我们对其在哺乳动物生理学中发挥的作用仍认知有限。本研究针对保守型长链非编码RNA Norad的体内生理学功能开展了探究。在小鼠中敲除Norad基因会引发基因组不稳定性与线粒体功能障碍，进而导致类似早衰的严重多系统退行性表型。Norad缺陷型动物出现的组织稳态失衡，可归因于PUMILIO蛋白活性增强；该类蛋白可作为结合靶mRNA的转录后抑制因子。在小鼠组织中，Norad是PUMILIO2（PUM2）的优选RNA靶标；当Norad缺失时，PUM2会过度抑制有丝分裂与线粒体功能所需的关键基因。据此，强制过表达Pum2可完全模拟Norad基因敲除的表型，引发快速发作的衰老相关表型。本研究结果为解析非编码RNA与RNA结合蛋白在正常生理及衰老过程中的作用提供了新见解，并开辟了全新的研究方向。本研究通过RNA测序（RNA-seq）测定了基因表达谱。