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RecA‐independent recombination: Dependence on the Escherichia coli RarA protein
Author(s) -
Jain Kanika,
Wood Elizabeth A.,
Romero Zachary J.,
Cox Michael M.
Publication year - 2021
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.14655
Subject(s) - recombination , flp frt recombination , homologous recombination , biology , recombinase , genetics , non allelic homologous recombination , cre lox recombination , genetic recombination , site specific recombination , helicase , dna , plasmid , ectopic recombination , escherichia coli , gene , rna , transgene , genetically modified mouse
Most, but not all, homologous genetic recombination in bacteria is mediated by the RecA recombinase. The mechanistic origin of RecA‐independent recombination has remained enigmatic. Here, we demonstrate that the RarA protein makes a major enzymatic contribution to RecA‐independent recombination. In particular, RarA makes substantial contributions to intermolecular recombination and to recombination events involving relatively short (<200 bp) homologous sequences, where RecA‐mediated recombination is inefficient. The effects are seen here in plasmid‐based recombination assays and in vivo cloning processes. Vestigial levels of recombination remain even when both RecA and RarA are absent. Additional pathways for RecA‐independent recombination, possibly mediated by helicases, are suppressed by exonucleases ExoI and RecJ. Translesion DNA polymerases may also contribute. Our results provide additional substance to a previous report of a functional overlap between RecA and RarA.