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Integrons and gene cassettes: hotspots of diversity in bacterial genomes
Author(s) -
Hall Ruth M.
Publication year - 2012
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.2012.06588.x
Subject(s) - integron , gene cassette , recombinase , bacterial genome size , biology , transposable element , genetics , genome , mobile genetic elements , gene , plasmid , computational biology , recombination
Integrons are genetic units found in many bacterial species that are defined by their ability to capture small mobile elements called gene cassettes. Cassettes usually contain only one gene, potentially any gene, and an attC recombination site, and thousands of cassettes have been sequenced. A specialized IntI site–specific recombinase encoded by the integron recognizes attC and incorporates cassettes into an attI site located adjacent to the intI gene. Over 100 types of integrons have been found, most in bacterial chromosomes. They can all potentially share the same cassettes and, as recombination between attC in a cassette and an attI can occur repeatedly, an integron can contain from zero to hundreds of cassettes. Cassette arrays that are not located next to an intI gene, or solo cassettes at apparently random sites, are also seen. Hence, integrons contribute to generation of diversity in bacterial, plasmid, and transposon genomes and facilitate extensive sharing of information among bacteria.