RT Journal Article SR Electronic T1 Recombination proteins differently control the acquisition of homeologous DNA during Bacillus subtilis natural chromosomal transformation JF bioRxiv FD Cold Spring Harbor Laboratory SP 2020.05.13.090589 DO 10.1101/2020.05.13.090589 A1 Serrano, Ester A1 Ramos, Cristina A1 Alonso, Juan C. A1 Ayora, Silvia YR 2020 UL http://biorxiv.org/content/early/2020/05/13/2020.05.13.090589.abstract AB In naturally competent Bacillus subtilis cells the acquisition of closely related genes occurs via homology-directed chromosomal transformation (CT), and its frequency decreases log-linearly with increased sequence divergence (SD) up to 15%. Beyond this and up to 23% SD the interspecies boundary prevails, the CT frequency marginally decreases, and short (<10-nucleotides) segments are integrated via homology-facilitated micro-homologous integration. Both poorly known CT mechanisms are RecA-dependent. Here we identify the recombination proteins required for the acquisition of interspecies DNA. The absence of AddAB, RecF, RecO, RuvAB or RecU, crucial for repair-by-recombination, does not affect CT. However, inactivation of dprA, radA, recJ, recX or recD2 strongly interfered with CT. Interspecies CT was abolished beyond ~8% SD in ΔdprA, ~10% in ΔrecJ, ΔradA, ΔrecX and 14% in ΔrecD2 cells. We propose that DprA, RecX, RadA/Sms, RecJ and RecD2 help RecA to unconstrain speciation and gene flow. These functions are ultimately responsible for generating genetic diversity and facilitate CT and gene acquisition from bacteria of the same genus.Competing Interest StatementThe authors have declared no competing interest.