Proper regulation of mRNA production in the nucleus is critical for the maintenance of cellular homoeostasis during adaptation to internal and environmental cues. Over the past 25 years, it has become clear that the nuclear machineries governing gene transcription, pre-mRNA processing, pre-mRNA and mRNA decay, and mRNA export to the cytoplasm are inextricably linked to control the quality and quantity of mRNAs available for translation. More recently, an ever-expanding diversity of new mechanisms by which nuclear RNA decay factors finely tune the expression of protein-encoding genes have been uncovered. Here, we review the current understanding of how mammalian cells shape their protein-encoding potential by regulating the decay of pre-mRNAs and mRNAs in the nucleus. In this Review, the authors summarize our current understanding of nuclear pre-mRNA and mRNA decay pathways. They describe how aberrantly processed mRNAs are targeted for decay in the nucleus and how this process is regula

米大統領選の投開票日前後で、新しいSNS「Bluesky」（ブルースカイ）の利用者が急増している。背景には、X（旧ツイッター）を率い、トランプ次期米政権で要職…