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Recombination proteins differently control the acquisition of homeologous DNA during Bacillus subtilis natural chromosomal transformation
Author(s) -
Serrano Ester,
Ramos Cristina,
Alonso Juan C.,
Ayora Silvia
Publication year - 2021
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.15342
Subject(s) - biology , bacillus subtilis , prokaryote , homology (biology) , homologous recombination , dna , genetics , transformation (genetics) , recombination , gene , bacteria , microbiology and biotechnology
Summary Natural chromosomal transformation (CT) plays a major role in prokaryote evolution, yet factors that govern the integration of DNA from related species remain poorly understood. We show that in naturally competent Bacillus subtilis cells the acquisition of homeologous sequences is governed by sequence divergence (SD). Integration initiates in a minimal efficient processing segment via homology‐directed CT, and its frequency decreases log‐linearly with increased SD up to 15%. Beyond this and up to 23% SD the interspecies boundaries prevail, the CT frequency marginally decreases, and short (<10‐nucleotides) segments are integrated via homology‐facilitated micro‐homologous integration. Both mechanisms are RecA dependent. We identify the other recombination proteins required for the acquisition of homeologous DNA. The absence of AddAB, RecF, RecO, RuvAB or RecU, crucial for repair‐by‐recombination, did not affect CT. However, dprA , radA , recJ , recX or recD2 inactivation strongly decreased intraspecies and interspecies CT. Interspecies CT was not detected beyond ~8% SD in Δ dprA , ~10% in Δ recJ , Δ radA , Δ recX and ~14% in Δ recD2 cells. We propose that DprA, RecX, RadA/Sms, RecJ and RecD2 accessory proteins are important for the generation of genetic diversity. Together with RecA, they facilitate gene acquisition from bacteria of related species.