{Reference Type}: Journal Article {Title}: Capture of armA by a novel ISCR element, ISCR28. {Author}: Yuan M;Nie L;Huang Z;Xu S;Qiu X;Han L;Kang Y;Li F;Yao J;Li Q;Li H;Li D;Zhu X;Li Z; {Journal}: Int J Antimicrob Agents {Volume}: 64 {Issue}: 3 {Year}: 2024 Jun 20 {Factor}: 15.441 {DOI}: 10.1016/j.ijantimicag.2024.107250 {Abstract}: ISCR28 is a fully functional and active member of the IS91-like family of insertion sequences. ISCR28 is 1,708-bp long and contains a 1,293-bp long putative open reading frame that codes a transposase. Sixty ISCR28-containing sequences from GenBank generated 27 non-repeat genetic contexts, all of which represented naturally occurring biological events that had occurred in a wide range of gram-negative organisms. Insertion of ISCR28 into target DNA preferred the presence of a 5'-GXXT-3' sequence at its terIS (replication terminator) end. Loss of the first 4 bp of its oriIS (origin of replication) likely caused ISCR28 to be trapped in ISApl1-based transposons or similar structures. Loss of terIS and fusion with a mobile element upstream likely promoted co-transfer of ISCR28 and the downstream resistance genes. ArmA and its downstream intact ISCR28 can be excised from recombinant pKD46 plasmids forming circular intermediates, further elucidating its activity as a transposase.