Co‐evolution with recombination affects the stability of mobile genetic element insertions within gene families of Salmonella. Issue 6 (25th April 2018)

• Record Type: Journal Article
• Authors: Brandis, Gerrit; Cao, Sha; Hughes, Diarmaid
• Is Part Of: Molecular microbiology. Volume 108:Issue 6(2018)
• Page Start: 697
• Page End: 710
• Publication Date: 2018-04-25
• Subjects: Molecular microbiology -- Periodicals; 572.829
• DOI: 10.1111/mmi.13959
• Languages: English
• ISSNs: 0950-382X

Abstract

Summary: Bacteria can have multiple copies of a gene at separate locations on the same chromosome. Some of these gene families, including tuf (translation elongation factor EF‐Tu) and rrl (ribosomal RNA), encode functions critically important for bacterial fitness. Genes within these families are known to evolve in concert using homologous recombination to transfer genetic information from one gene to another. This mechanism can counteract the detrimental effects of nucleotide sequence divergence over time. Whether such mechanisms can also protect against the potentially lethal effects of mobile genetic element insertion is not well understood. To address this we constructed two different length insertion cassettes to mimic mobile genetic elements and inserted these into various positions of the tuf and rrl genes. We measured rates of recombinational repair that removed the inserted cassette and studied the underlying mechanism. Our results indicate that homologous recombination can protect the tuf and rrl genes from inactivation by mobile genetic elements, but for insertions within shorter gene sequences the efficiency of repair is very low. Intriguingly, we found that physical distance separating genes on the chromosome directly affects the rate of recombinational repair suggesting that relative location will influence the ability of homologous recombination to maintain homogeneity. Abstract : Gene families with multiple copies of the same gene separately located on the chromosome are a frequent feature in prokaryotic and eukaryotic organisms. These gene families present a potential target site for integration of mobile genetic elements. Our results indicate that homologous recombination can protect genes within gene families from inactivation by mobile genetic elements, but for shorter gene sequences the efficiency of repair is very low.