A dual role for mycobacterial RecO in RecA-dependent homologous recombination and RecA-independent single-strand annealing |
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| Authors: | Richa Gupta Mikhail Ryzhikov Olga Koroleva Mihaela Unciuleac Stewart Shuman Sergey Korolev Michael S Glickman |
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| Institution: | 1.Division of Infectious Diseases, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA, 2.Immunology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA, 3.Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, 1100 South Grand boulevard, St. Louis, MO 63021, USA and 4.Molecular Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA |
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| Abstract: | Mycobacteria have two genetically distinct pathways for the homology-directed repair of DNA double-strand breaks: homologous recombination (HR) and single-strand annealing (SSA). HR is abolished by deletion of RecA and reduced in the absence of the AdnAB helicase/nuclease. By contrast, SSA is RecA-independent and requires RecBCD. Here we examine the function of RecO in mycobacterial DNA recombination and repair. Loss of RecO elicits hypersensitivity to DNA damaging agents similar to that caused by deletion of RecA. We show that RecO participates in RecA-dependent HR in a pathway parallel to the AdnAB pathway. We also find that RecO plays a role in the RecA-independent SSA pathway. The mycobacterial RecO protein displays a zinc-dependent DNA binding activity in vitro and accelerates the annealing of SSB-coated single-stranded DNA. These findings establish a role for RecO in two pathways of mycobacterial DNA double-strand break repair and suggest an in vivo function for the DNA annealing activity of RecO proteins, thereby underscoring their similarity to eukaryal Rad52. |
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