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Heteromeric transposase elements: generators of genomic islands across diverse bacteria
Author(s) -
Peters Joseph E.,
Fricker Ashwana D.,
Kapili Bennett J.,
Petassi Michael T.
Publication year - 2014
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.12740
Subject(s) - biology , transposase , transposable element , bacteria , dna transposable elements , genetics , computational biology , evolutionary biology , genome , gene
Summary Horizontally acquired genetic information in bacterial chromosomes accumulates in blocks termed genomic islands. Tn 7 ‐like transposons form genomic islands at a programmed insertion site in bacterial chromosomes, attTn7 . Transposition involves five transposon‐encoded genes ( tnsABCDE ) including an atypical heteromeric transposase. One transposase subunit, TnsB , is from the large family of bacterial transposases, the second, TnsA , is related to endonucleases. A regulator protein, TnsC , functions with different target site selecting proteins to recognize different targets. TnsD directs transposition into attTn7 , while TnsE encourages horizontal transmission by targeting mobile plasmids. Recent work suggests that distantly related elements with heteromeric transposases exist with alternate targeting pathways that also facilitate the formation of genomic islands. Tn 6230 and related elements can be found at a single position in a gene of unknown function ( yhiN ) in various bacteria as well as in mobile plasmids. Another group we term Tn 6022 ‐like elements form pathogenicity islands in the A cinetobacter baumannii comM gene. We find that Tn 6022 ‐like elements also appear to have an uncharacterized mechanism for provoking internal transposition and deletion events that serve as a conduit for evolving new elements. As a group, heteromeric transposase elements utilize diverse target site selection mechanisms adapted to the spread and rearrangement of genomic islands.