The Transposon Registry

Tn7519 is a 11,664 bp predicted transposon carried by an IncF plasmid in a Pantoea isolate from equine faeces. The element encodes a predicted site-specific transposase (tyrosine recombinase) distantly related to that of the Staphylococcus aureus element Tn554 (13% aa identity, 29% aa similarity). The element carries a copper resistance gene cluster (copABCDRS) as the primary cargo. Evidence that this is a genuine transposon comes from analysis of the flanking sequences, ie. this 11,664 bp region has precisely interrupted an umuC gene. Note that Tn554 family elements do not have characteristic inverted repeats and do not leave direct repeats either (see EMBO J 7:2935), and thus the absence of these features is in keeping with predictions based on the phylogeny of the transposase gene.

Tn7523 has 22 open reading frames (orfs). It is bounded by imperfect inverted repeats of 26 bp. The first 5 orfs correspond to tniC, tniA, tniB, tniD, and tniE similarly to other members of the Tn6019 family. orfs 6 to 22 encode a variety of proteins such as transporters, regulatory protein RecX (PRK14135), carboxymuconolactone decarboxylase, ferredoxin-NADP(+) reductase, NAD(P)H-dependent oxidoreductase, redox-sensitive transcriptional activator SoxR, ThiF family adenylyltransferase, nucleotidyltransferase, ImmA/IrrE family metallo-endopeptidase, and metallophosphoesterase. Tn7523 also has a novel insertion sequence (IS) element between orf15 and orf16. This IS (1243 bp) has 1021/1243 (82%) nucleotide identity to ISAcsp3. Tn7523 was found inserted in the chromosomal gene comM of Acinetobacter baumannii strain ATCC 17961.