Fig. 1From: Resistance integrons: class 1, 2 and 3 integronsSchematic representation of a class 1 integron. P1 promoter for transcription of gene cassettes, P2 second promoter that is usually inactive, int integrase gene, attI1 integration site, qacE partially deleted gene that encodes quaternary ammonium compound resistance, sulI sulphonamide resistance, orf5 unknown function, P promoters of the qacE△ and sulI genes, attC sequence on the gene cassette recognized by the integraseBack to article page