Bacillus subtilis diadenylate cyclase DisA converts two ATPs into c-di-AMP, but this activity is suppressed upon interaction with sites of DNA damage. DisA forms a rapid moving focus that pauses upon induction of DNA damage during spore development. We report that DisA pausing, however, was not observed in the absence of the RecO mediator or of the RecA recombinase, suggesting that DisA binds to recombination intermediates formed by RecA in concert with RecO. DisA, which physically interacts with RecA, was found to reduce its ATPase activity without competing for nucleotides or ssDNA. Furthermore, increasing DisA concentrations inhibit RecA-mediated DNA strand exchange, but this inhibition failed to occur when RecA was added prior to DisA, and was independent of RecA-mediated nucleotide hydrolysis or increasing concentrations of c-di-AMP. We propose that DisA may preserve genome integrity by downregulating RecA activities at several steps of the DNA damage tolerance pathway, allowing time for the repair machineries to restore genome stability. DisA might reduce RecA-mediated template switching by binding to a stalled or reversed fork.
Bibliographical noteFunding Information:
Ministerio de Economía, Industria y Competitividad (MINECO)/FEDER) [BFU2015-67065-P, PGC2018-097054-B-I00 to J.C.A.]; R.T. is a PhD fellow of La Caixa Foundation International Fellowship Program (La Caixa/CNB) and his stay in Jerusalem was supported by an EMBO Short-Term Fellowship [7425; S.B.Y. is supported by the European Research Council Advanced Grant . Funding for open access charge: MINECO)/FEDER [BFU2015-67065-P].
© 2019 The Author(s) 2019. Published by Oxford University Press on behalf of Nucleic Acids Research.