RT Journal Article
T1 Efficiency of integron cassette insertion in correct orientation is ensured by the interplay of the three unpaired features of attC recombination sites
A1 Nivina, Aleksandra
A1 Escudero García-Calderón, José Antonio
A1 Vit, Claire
A1 Mazel, Didier
A1 Loot, Céline
AB The integron is a bacterial recombination system that allows acquisition, stockpiling and expression of cassettes carrying protein-coding sequences, and is responsible for the emergence and rise of multiresistance in Gram-negative bacteria. The functionality of this system depends on the insertion of promoterless cassettes in correct orientation, allowing their expression from the promoter located upstream of the cassette array. Correct orientation is ensured by strand selectivity of integron integrases for the bottom strand of cassette recombination sites (attC), recombined in form of folded single-stranded hairpins. Here, we investigated the basis of such strand selectivity by comparing recombination of wild-type and mutated attC sites with different lengths, sequences and structures. We show that all three unpaired structural features that distinguish the bottom and top strands contribute to strand selectivity. The localization of Extra-Helical Bases (EHBs) directly favors integrase binding to the bottom strand. The Unpaired Central Spacer (UCS) and the Variable Terminal Structure (VTS) influence strand selectivity indirectly, probably through the stabilization of the bottom strand and the resulting synapse due to the nucleotide skew between the two strands. These results underscore the importance of the single-stranded nature of the attC site that allows such tight control over integron cassette orientation.
PB Oxford Academic
SN 0305-1048
YR 2016
FD 2016
LK https://hdl.handle.net/20.500.14352/117028
UL https://hdl.handle.net/20.500.14352/117028
LA eng
NO Aleksandra Nivina, José Antonio Escudero, Claire Vit, Didier Mazel, Céline Loot, Efficiency of integron cassette insertion in correct orientation is ensured by the interplay of the three unpaired features of attC recombination sites, Nucleic Acids Research, Volume 44, Issue 16, 19 September 2016, Pages 7792–7803, https://doi.org/10.1093/nar/gkw646
NO FP-7-PEOPLE-2011-IEF, ICADIGE to J.A.E.
NO Centre National de la Recherche Scientifique
NO French National Research Agency
NO Paris Descartes University
NO Institut Pasteur
NO European Commission
DS Docta Complutense
RD 9 abr 2025