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Four genes, two ends, and a res region are involved in transposition of Tn 5053 : a paradigm for a novel family of transposons carrying either a mer operon or an integron
Author(s) -
Kholodii G.Ya.,
Mindlin S.Z.,
Bass I.A.,
Yurieva O.V.,
Minakhina S.V.,
Nikiforov V.G.
Publication year - 1995
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/j.1365-2958.1995.mmi_17061189.x
Subject(s) - transposable element , biology , genetics , transposition (logic) , insertion sequence , integron , gene , inverted repeat , plasmid , genome , linguistics , philosophy
The complete nucleotide sequence of an 8447 bp‐long mercury‐resistance transposon (Tn 5053 ) has been determined. Tn 5053 is composed of two modules: (i) the mercury‐resistance module and (ii) the transposition module. The mercury‐resistance module carries a mer operon, merRTPFAD , and appears to be a single‐ended relic of a transposon closely related to the classical mercury‐resistance transposons Tn 21 and Tn 501 . The transposition module of Tn 5053 is bounded by 25 bp terminal inverted repeats and contains four genes involved in transposition, i.e. tniA, tniB, tniQ , and tniR . Transposition of Tn 5053 occurs via cointegrate formation mediated by the products of the tniABQ genes, followed by site‐specific cointegrate resolution. This is catalysed by the product of the tniR gene at the res region, which is located upstream of tniR . The same pathway of transposition is used by Tn 402 (Tn 5090 ) which carries the integron of R751. Transposition genes of Tn 5053 and Tn 402 are interchangeable. Sequence analysis suggests that Tn 5053 and Tn 402 are representatives of a new family of transposable elements, which fall into a recently recognized superfamily of transposons including retroviruses, insertion sequences of the IS 3 family, and transposons Tn 552 and Tn 7 . We suggest that the tni genes were involved in the dissemination of integrons.