Tn3 transposon

The Tn3 transposon is a 4957 base pair mobile genetic element, found in prokaryotes. It encodes three proteins:

• β-lactamase, an enzyme that confers resistance to β-lactam antibiotics (and is encoded by the gene bla).
• Tn3 transposase (encoded by gene tnpA)
• Tn3 resolvase (encoded by gene tnpR)

Tn3 is an example of replicative transposon (Copy-Paste type transposone).

Initially discovered as a repressor of transposase, resolvase also plays a role in facilitating Tn3 replication (Sherratt 1989).

The transposon is flanked by a pair of 38bp inverted repeats.