Alternative interactions between the Tn7 transposase and the Tn7 target DNA binding protein regulate target immunity and transposition.

Zachary Skelding; Jennie Queen-Baker; Nancy L Craig

doi:10.1093/emboj/cdg551

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Alternative interactions between the Tn7 transposase and the Tn7 target DNA binding protein regulate target immunity and transposition.

Zachary Skelding·Jennie Queen-Baker·Nancy L Craig

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Abstract

The Tn7 transposon avoids inserting into a target DNA that contains a pre-existing copy of Tn7. This phenomenon, known as 'target immunity', is established when TnsB, a Tn7 transposase subunit, binds to Tn7 sequences in the target DNA and mediates displacement of TnsC, a critical transposase activator, from the DNA. Paradoxically, TnsB-TnsC interactions are also required to promote transposon insertion. We have probed Tn7 target immunity by isolating TnsB mutants that mediate more frequent insertions into a potentially immune target DNA because they fail to provoke dissociation of TnsC from the DNA. We show that a single region of TnsB mediates the TnsB-TnsC interaction that underlies both target immunity and transposition, but that TnsA, the other transposase subunit, channels the TnsB-TnsC interaction toward transposition.

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Amino Acid Sequence Bacteriophage mu DNA Transposable Elements DNA, Bacterial DNA-Binding Proteins Escherichia coli Escherichia coli Proteins Molecular Sequence Data Mutation Transposases Journal Article Research Support, U.S. Gov't, P.H.S.

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Zachary Skelding, Jennie Queen-Baker, Nancy L Craig. 2003-11-03. Alternative interactions between the Tn7 transposase and the Tn7 target DNA binding protein regulate target immunity and transposition.. https://doi.org/10.1093/emboj%2Fcdg551

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