XRN 5'→3' exoribonucleases: structure, mechanisms and functions

Nagarajan, Vinay K, Jones, Christopher I, Newbury, Sarah F and Green, Pamela J (2013) XRN 5'→3' exoribonucleases: structure, mechanisms and functions. BBA - Biochimica et Biophysica Acta- Gene Regulatory Mechanisms, 1829 (6-7). pp. 590-603. ISSN 0006-3002

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Abstract

The XRN family of 5′ → 3′ exoribonucleases is critical for ensuring the fidelity of cellular RNA turnover in eukaryotes. Highly conserved across species, the family is typically represented by one cytoplasmic enzyme (XRN1/PACMAN or XRN4) and one or more nuclear enzymes (XRN2/RAT1 and XRN3). Cytoplasmic and/or nuclear XRNs have proven to be essential in all organisms tested, and deficiencies can have severe developmental phenotypes, demonstrating that XRNs are indispensable in fungi, plants and animals. XRNs degrade diverse RNA substrates during general RNA decay and function in specialized processes integral to RNA metabolism, such as nonsense-mediated decay (NMD), gene silencing, rRNA maturation, and transcription termination. Here, we review current knowledge of XRNs, highlighting recent work of high impact and future potential. One example is the breakthrough in our understanding of how XRN1 processively degrades 5′ monophosphorylated RNA, revealed by its crystal structure and mutational analysis. The expanding knowledge of XRN substrates and interacting partners is outlined and the functions of XRNs are interpreted at the organismal level using available mutant phenotypes. Finally, three case studies are discussed in more detail to underscore a few of the most exciting areas of research on XRN function: XRN4 involvement in small RNA-associated processes in plants, the roles of XRN1/PACMAN in Drosophila development, and the function of human XRN2 in nuclear transcriptional quality control. This article is part of a Special Issue entitled: RNA Decay mechanisms.

Item Type: Article
Schools and Departments: Brighton and Sussex Medical School > Clinical and Experimental Medicine
Brighton and Sussex Medical School > Primary Care and Public Health
Subjects: Q Science > QH Natural history > QH0301 Biology > QH0426 Genetics > QH0447 Genes. Alleles. Genome
Depositing User: Sarah Newbury
Date Deposited: 28 Apr 2014 09:47
Last Modified: 11 Oct 2017 21:29
URI: http://sro.sussex.ac.uk/id/eprint/48295

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