RT Journal Article T1 The expression of integron arrays is shaped by the translation rate of cassettes A1 Carvalho, André A1 Hipólito, Alberto A1 Trigo da Roza, Filipa A1 García Pastor, Lucía A1 Vergara, Ester A1 Buendía, Aranzazu A1 García-Seco Romero, María Teresa A1 Escudero García-Calderón, José Antonio AB Integrons are key elements in the rise and spread of multidrug resistance in Gram-negative bacteria. These genetic platforms capture cassettes containing promoterless genes and stockpile them in arrays of variable length. In the current integron model, expression of cassettes is granted by the Pc promoter in the platform and is assumed to decrease as a function of its distance. Here we explored this model using a large collection of 136 antibiotic resistance cassettes and show the effect of distance is in fact negligible. Instead, cassettes have a strong impact in the expression of downstream genes because their translation rate affects the stability of the whole polycistronic mRNA molecule. Hence, cassettes with reduced translation rates decrease the expression and resistance phenotype of cassettes downstream. Our data puts forward an integron model in which expression is contingent on the translation of cassettes upstream, rather than on the distance to the Pc. PB Springer Nature SN 2041-1723 YR 2024 FD 2024-10-25 LK https://hdl.handle.net/20.500.14352/110146 UL https://hdl.handle.net/20.500.14352/110146 LA eng NO Carvalho, A., Hipólito, A., Trigo da Roza, F., García-Pastor, L., Vergara, E., Buendía, A., García-Seco, T., & Escudero, J. A. (2024). The expression of integron arrays is shaped by the translation rate of cassettes. Nature communications, 15(1), 9232. https://doi.org/10.1038/s41467-024-53525-6 NO Acknowledgements:We would like to thank José R. Penadés for the helpful discussions and for the critical reading of the manuscript. We are grateful to all the members of the MBA lab for the helpful discussion. The work in the MBA laboratory is supported by the European Research Council (ERC) through a Starting Grant [ERC grant no. 803375-KRYPTONINT] and the Ministerio de Ciencia e Innovación [PID2020-117499RB-100 and CNS2022-135857]; J.A.E. has been supported by the Atracción de Talento Program of the Comunidad de Madrid [2016-T1/BIO-1105 and 2020-5A/BIO19726]; A.H. is supported by the PhD program at UCM; F.T.R. is supported by the Portuguese Fundação para Ciência e a Tecnologia [SFRH/BD/144108/2019];Author contributionsA.C.: conceptualization, methodology, formal analysis, validation, andwriting-original draft. A.H.: conceptualization, methodology, formalanalysis, and validation. F.T.R.: methodology, formal analysis, and validation. L.G.P.: methodology, formal analysis, and validation; E.V.: methodology and formal analysis. A.B.: methodology. T.G.S.: methodology. J.A.E.: conceptualization, formal analysis, validation, and writing the final manuscript. All authors read, amended, and approved the final version of the manuscript NO Ministerio de Ciencia, Innovación y Universidades (España) NO European Commission NO Universidad Complutense de Madrid NO Comunidad de Madrid NO Portuguese Fundação para Ciência e a Tecnologia DS Docta Complutense RD 7 abr 2025