The RNA exosome: mechanisms of RNA surveillance, regulation, and disease

The RNA exosome is a conserved multi-subunit ribonuclease complex with pivotal roles in RNA biogenesis, surveillance, and processing. It comprises a nine-subunit scaffold that associates with distinct ribonucleases in a cell compartment-specific manner, contributing to the processing and turnover of a broad spectrum of nuclear and cytoplasmic transcripts, including pervasively transcribed and short-lived RNAs, precursors, and abortive and aberrant transcripts. In this review, we examine how the RNA exosome engages a wide spectrum of RNAs via differential adaptor usage and intrinsic substrate features, such as transcript length and 3' end structure. This also modulates the entry routes of the recruited transcripts. We highlight conserved principles and major differences between yeast and metazoans. We assimilate emerging evidence that suggests that the RNA exosome localization and activity are dynamically regulated in response to cellular context and external stimuli. Finally, drawing on findings from studies in S. cerevisiae, Drosophila, zebrafish, and mice, we discuss how perturbations in RNA surveillance can result in abnormalities in organismal development and homoeostasis. Together, these studies not only enhance our knowledge of the broader relevance of RNA quality control and metabolism but also provide mechanistic insights into pathomechanisms, particularly the tissue-specific vulnerabilities noted in RNA exosome-linked diseases.