RadB acts in homologous recombination in the archaeon Haloferax volcanii, consistent with a role as recombination mediator

Wardell, Kayleigh; Haldenby, Sam; Jones, Nathan; Liddell, Susan; Ngo, Greg H.P.; Allers, Thorsten

Abstract

Homologous recombination plays a central role in the repair of double-strand DNA breaks, the restart of stalled replication forks and the generation of genetic diversity. Regulation of recombination is essential since defects can lead to genome instability and chromosomal rearrangements. Strand exchange is a key step of recombination – it is catalysed by RecA in bacteria, Rad51/Dmc1 in eukaryotes and RadA in archaea. RadB, a paralogue of RadA, is present in many archaeal species. RadB has previously been proposed to function as a recombination mediator, assisting in RadA-mediated strand exchange. In this study, we use the archaeon Haloferax volcanii to provide evidence to support this hypothesis. We show that RadB is required for efficient recombination and survival following treatment with DNA-damaging agents, and we identify two point mutations in radA that suppress the ΔradB phenotype. Analysis of these point mutations leads us to propose that the role of RadB is to act as a recombination mediator, which it does by inducing a conformational change in RadA and thereby promoting its polymerisation on DNA.

Citation

Wardell, K., Haldenby, S., Jones, N., Liddell, S., Ngo, G. H., & Allers, T. (2017). RadB acts in homologous recombination in the archaeon Haloferax volcanii, consistent with a role as recombination mediator. DNA Repair, 55, https://doi.org/10.1016/j.dnarep.2017.04.005

• Journal Article Type: Article
• Acceptance Date: Apr 25, 2017
• Online Publication Date: Apr 26, 2017
• Publication Date: Jul 1, 2017
• Deposit Date: May 15, 2017
• Publicly Available Date: May 15, 2017
• Journal: DNA Repair
• Print ISSN: 1568-7864
• Electronic ISSN: 1568-7856
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 55
• DOI: https://doi.org/10.1016/j.dnarep.2017.04.005
• Keywords: Homologous recombination; Archaea; RecA-family recombinase; Strand exchange; Recombination mediator
• Public URL: https://nottingham-repository.worktribe.com/output/968104
• Publisher URL: http://www.sciencedirect.com/science/article/pii/S1568786415301117