A novel role for GSK3β as a modulator of Drosha microprocessor activity and MicroRNA biogenesis

Fletcher, C. E., Godfrey, J. D., Shibakawa, A., Bushell, M. and Bevan, C. L. (2017) A novel role for GSK3β as a modulator of Drosha microprocessor activity and MicroRNA biogenesis. Nucleic Acids Research, 45(5), pp. 2809-2828. (doi: 10.1093/nar/gkw938) (PMID:27907888) (PMCID:PMC5389555)

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Regulation of microRNA (miR) biogenesis is complex and stringently controlled. Here, we identify the kinase GSK3β as an important modulator of miR biogenesis at Microprocessor level. Repression of GSK3β activity reduces Drosha activity toward pri-miRs, leading to accumulation of unprocessed pri-miRs and reduction of pre-miRs and mature miRs without altering levels or cellular localisation of miR biogenesis proteins. Conversely, GSK3β activation increases Drosha activity and mature miR accumulation. GSK3β achieves this through promoting Drosha:cofactor and Drosha:pri-miR interactions: it binds to DGCR8 and p72 in the Microprocessor, an effect dependent upon presence of RNA. Indeed, GSK3β itself can immunoprecipitate pri-miRs, suggesting possible RNA-binding capacity. Kinase assays identify the mechanism for GSK3β-enhanced Drosha activity, which requires GSK3β nuclear localisation, as phosphorylation of Drosha at S300 and/or S302; confirmed by enhanced Drosha activity and association with cofactors, and increased abundance of mature miRs in the presence of phospho-mimic Drosha. Functional implications of GSK3β-enhanced miR biogenesis are illustrated by increased levels of GSK3β-upregulated miR targets following GSK3β inhibition. These data, the first to link GSK3β with the miR cascade in humans, highlight a novel pro-biogenesis role for GSK3β in increasing miR biogenesis as a component of the Microprocessor complex with wide-ranging functional consequences.

Item Type:Articles
Additional Information:The Wellcome Trust, The Rosetrees Trust, the Imperial Cancer Research UK Centre and Experimental Cancer Medicine Centre and a Movember/Prostate Cancer UK Centre of Excellence Program [CEO013-2-002]. FundIng for open access charge: Imperial College Open Access Fund.
Glasgow Author(s) Enlighten ID:Bushell, Professor Martin
Authors: Fletcher, C. E., Godfrey, J. D., Shibakawa, A., Bushell, M., and Bevan, C. L.
College/School:College of Medical Veterinary and Life Sciences > School of Cancer Sciences
Journal Name:Nucleic Acids Research
Publisher:Oxford University Press
ISSN (Online):1362-4962
Published Online:23 October 2016
Copyright Holders:Copyright © 2016 The Authors
First Published:First published in Nucleic Acids Research 45(5): 2809-2828
Publisher Policy:Reproduced under a Creative Commons License

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