Blanco Torres, PaulaTrigo da Roza, FilipaToribio Celestino, LauraGarcía Pastor, LucíaCaselli, NiccoloMorón García, ÁlvaroOjeda, FranciscoDarracq, BaptisteVergara, EsterAmaro Torres, FranciscoSan Millán, ÁlvaroSkovgaard, OleMazel, DidierLoot, CélineEscudero García-Calderón, José Antonio2024-10-232024-10-2320240305-104810.1093/nar/gkae866https://hdl.handle.net/20.500.14352/1093432016-T1/BIO-1105, 2020-5A/BIO-19726 para J.A.E. FJC 2020-043017-I para P.B. SFRH/BD/144108/2019 para F.T.R. CNRS-UMR3525 para B.D., D.M., C.L. EQU202103012569 para D.M.Integrons are genetic elements that increase the evolvability of bacteria by capturing new genes and stockpiling them in arrays. Sedentary chromosomal integrons (SCIs) can be massive and highly stabilized structures encoding hundreds of genes, whose function remains generally unknown. SCIs have co-evolved with the host for aeons and are highly intertwined with their physiology from a mechanistic point of view. But, paradoxically, other aspects, like their variable content and location within the genome, suggest a high genetic and functional independence. In this work, we have explored the connection of SCIs to their host genome using as a model the Superintegron (SI), a 179-cassette long SCI in the genome of Vibrio cholerae N16961. We have relocated and deleted the SI using SeqDelTA, a novel method that allows to counteract the strong stabilization conferred by toxin–antitoxin systems within the array. We have characterized in depth the impact in V. cholerae’s physiology, measuring fitness, chromosome replication dynamics, persistence, transcriptomics, phenomics, natural competence, virulence and resistance against protist grazing. The deletion of the SI did not produce detectable effects in any condition, proving that—despite millions of years of co-evolution—SCIs are genetically and functionally isolated units of genomes.engAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/journal article1362-4962https://doi.org/10.1093/nar/gkae86639385642open access575Genética2409 Genética