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Formation of a nucleoprotein complex containing Tn 7 and its target DNA regulates transposition initiation
Author(s) -
Skelding Zachary,
Sarnovsky Robert,
Craig Nancy L.
Publication year - 2002
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdf347
Subject(s) - transposase , transposable element , biology , nucleoprotein , transposition (logic) , dna , protein subunit , tn10 , dna binding protein , microbiology and biotechnology , genetics , mutant , gene , transcription factor , linguistics , philosophy
Tn 7 insertion into its specific target site, attTn7 , is mediated by the proteins TnsA, TnsB, TnsC and TnsD. The double‐strand breaks that separate Tn 7 from the donor DNA require the Tns proteins, the transposon and an attTn7 target DNA, suggesting that a prerequisite for transposition is the formation of a nucleoprotein complex containing TnsABC+D, and these DNAs. Here, we identify a TnsABC+D transposon– attTn7 complex, and demonstrate that it is a transposition intermediate. We demonstrate that an interaction between TnsB, the transposase subunit that binds to the transposon ends, and TnsC, the target DNA‐binding protein that controls the activity of the transposase, is essential for assembly of the TnsABC+D transposon– attTn7 complex. We also show that certain TnsB residues are required for recombination because they mediate a TnsB–TnsC interaction critical to formation of the TnsABC+D transpo son– attTn7 complex. We demonstrate that TnsA, the other transposase subunit, which also interacts with TnsC, greatly stabilizes the TnsABC+D transpo son– attTn7 complex. Thus multiple interactions between the transposase subunits, TnsA and TnsB, and the target‐binding transposase activator, TnsC, control Tn 7 transposition.