Trypanosoma brucei BRCA2 acts in a life cycle-specific genome stability process and dictates BRC repeat number-dependent RAD51 subnuclear dynamics

Trenaman, A., Hartley, C., Prorocic, M., Passos-Silva, D. G., van den Hoek, M., Nechyporuk-Zloy, V., Machado, C. R. and McCulloch, R. (2013) Trypanosoma brucei BRCA2 acts in a life cycle-specific genome stability process and dictates BRC repeat number-dependent RAD51 subnuclear dynamics. Nucleic Acids Research, 41(2), pp. 943-960. (doi:10.1093/nar/gks1192)

[img]
Preview
Text
74678.pdf - Published Version
Available under License Creative Commons Attribution.

12MB

Abstract

Trypanosoma brucei survives in mammals through antigenic variation, which is driven by RAD51-directed homologous recombination of Variant Surface Glycoproteins (VSG) genes, most of which reside in a subtelomeric repository of >1000 silent genes. A key regulator of RAD51 is BRCA2, which in T. brucei contains a dramatic expansion of a motif that mediates interaction with RAD51, termed the BRC repeats. BRCA2 mutants were made in both tsetse fly-derived and mammal-derived T. brucei, and we show that BRCA2 loss has less impact on the health of the former. In addition, we find that genome instability, a hallmark of BRCA2 loss in other organisms, is only seen in mammal-derived T. brucei. By generating cells expressing BRCA2 variants with altered BRC repeat numbers, we show that the BRC repeat expansion is crucial for RAD51 subnuclear dynamics after DNA damage. Finally, we document surprisingly limited co-localization of BRCA2 and RAD51 in the T. brucei nucleus, and we show that BRCA2 mutants display aberrant cell division, revealing a function distinct from BRC-mediated RAD51 interaction. We propose that BRCA2 acts to maintain the huge VSG repository of T. brucei, and this function has necessitated the evolution of extensive RAD51 interaction via the BRC repeats, allowing re-localization of the recombinase to general genome damage when needed.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Machado, Professor Carlos and McCulloch, Professor Richard and Trenaman, Miss Anna and van den Hoek, Ms Moniek and Nechyporuk-Zloy, Dr Volodymyr and Prorocic, Dr Marko
Authors: Trenaman, A., Hartley, C., Prorocic, M., Passos-Silva, D. G., van den Hoek, M., Nechyporuk-Zloy, V., Machado, C. R., and McCulloch, R.
College/School:College of Medical Veterinary and Life Sciences > Institute of Infection Immunity and Inflammation
Journal Name:Nucleic Acids Research
Publisher:Oxford University Press
ISSN:0305-1048
ISSN (Online):1362-4962
Published Online:12 December 2012
Copyright Holders:Copyright © 2013 The Authors
First Published:First published in Nucleic Acids Research 41(2):943-960
Publisher Policy:Reproduced under a Creative Commons License
Related URLs:

University Staff: Request a correction | Enlighten Editors: Update this record

Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
473571Trypanosoma brucei BRCA2 - at a crossroads between antigenic variation, homologous recombination and DNA replication?Richard MccullochWellcome Trust (WELLCOME)083223/Z/07/ZIII - BACTERIOLOGY
515891Chromosomal recombination and repair in African trypanosomesRichard MccullochWellcome Trust (WELLCOME)089172/Z/09/ZIII - BACTERIOLOGY
371796The Wellcome Centre for Molecular Parasitology ( Core Support )Andrew WatersWellcome Trust (WELLCOME)085349/Z/08/ZIII - PARASITOLOGY
371798The Wellcome Centre for Molecular Parasitology ( Core Support )Andrew WatersWellcome Trust (WELLCOME)085349/B/08/ZIII - PARASITOLOGY