Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q9UIJ5 (Rec)
 58,342 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tn9 is a transposable element in which a gene (cat) determining chloramphenicol resistance is flanked by directly repeated sequences that are homologous to the insertion sequence IS1. We show here that infection of Escherichia coli K12 (under Rec-Red-Int- conditions) with a lambda bio transducing phage carrying Tn9 results in the formation of lambda bio transductants as frequently as cat transductants as frequently as cat transductants (about 1 per 10(6) to 10(7) infected cells). Most of the lambda bio transductants do not carry cat, just as most of the cat transductants do not carry lambda bio. In spite of the absence of cat, the lambda bio prophage can transpose a second time, from the E. coli chromosome to different sites on an F'gal plasmid. Analysis of the structure of the transposed lambda bio element, by restriction nuclease digestion and by electron microscopy, demonstrates that the integrated lambda bio prophage is flanked by directly repeated IS1 elements. We conclude that there is no genetic information for the ability to transpose encoded in the non-repeated portion of Tn9, i.e. that the directly repeated IS1 elements alone are responsible for Tn9 transposition.
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PMID:Transposition of IS1-lambdaBIO-IS1 from a bacteriophage lambda derivative carrying the IS1-cat-IS1 transposon (Tn9). 624 15

Transduction with phage derived from a 2-year-old lysate of lambda cam105 (lambda::Tn9) gave rise to chloramphenicol-resistant (Cm(r)) transductants harboring a plasmid (plambdaCM1) formed from lambda cam105 by a Tn9-mediated adjacent deletion to position 36.07 kilobases in the N cistron of lambda. The plambdaCM element can replicate as a plasmid, insert into the bacterial genome, or reproduce lytically as a phage on cells that provide N function. The feasibility of obtaining high titers in encapsidated form and the ease of synchronous introduction into and recovery from bacterial populations make plambdaCM very suitable for quantitative studies of recombination involving transposable elements. Replicon fusions between plambdaCM1 and RSF1596 (pMB8::Tn3Delta596) occur by duplication of either IS1 (at low rate in the absence of TnpA activity) or Tn3Delta596 (in the presence of TnpA activity). At 24 or 32 degrees C, the rate of increase of TnpA-mediated fusions per plambdaCM is about 2% per cell doubling. RSF103 contains the deleted Tn1DeltaAp (which lacks intact beta-lactamase and TnpR resolvase coding sequences) adjacent to a streptomycin resistance (Sm(r)) determinant. We observed that Tn1DeltaAp mediates insertions of external RSF103 sequences into the R388 plasmid. R388::Tn1DeltaAp plasmids show transposition immunity in cells lacking TnpR activity. Using the plambdaCM system, we isolated adjacent transpositions of the RSF103 Sm(r) determinant. The resulting plambdaCM-Sm cosmids contain Sm(r) genetic material flanked by direct repeats of Tn1DeltaAp, and all are deleted for some RSF103 or plambdaCM sequences. The plambdaCM-Sm constructs will fuse into R388 by duplication of a single Tn1DeltaAp element. In the presence of tnpR(+) (but not tnpR) Tn1 or Tn3 elements, all Tn1DeltaAp-mediated complex replicons break down completely and rapidly to simple Tn1DeltaAp inserts. The equilibrium for resolution is at least 10(5):1, and resolution is more than 90% complete after 40 min of exposure to a tnpR(+) cytoplasm. In the absence of TnpR, Rec, and Red activities, Tn1DeltaAp-mediated complex replicons yield simple Tn1DeltaAp inserts at a lower rate. The presence of intact RSF103 replication determinants between direct Tn1DeltaAp repeats appears to accelerate this precise TnpR- and Rec-independent breakdown.
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PMID:p lambda CM system: observations on the roles of transposable elements in formation and breakdown of plasmids derived from bacteriophage lambda replicons. 629 61