biostudies-literatureGirard JAgence Nationale de la Recherche (ANR)French Infrastructure for Integrated Structural Biology (FRISBI)French Infrastructure for Integrated Structural BiologyAgence Nationale de la RechercheFondation pour la Recherche Médicale (FRM)Fondation pour la Recherche Médicalee0036824https://www.ebi.ac.uk/biostudies/studies/S-EPMC11265437biostudies-literatureUnknown98(7)Chikungunya virus (CHIKV) is a mosquito-borne pathogen responsible for an acute musculoskeletal disease in humans. Replication of the viral RNA genome occurs in specialized membranous replication organelles (ROs) or spherules, which contain the viral replication complex. Initially generated by RNA synthesis-associated plasma membrane deformation, alphavirus ROs are generally rapidly endocytosed to produce type I cytopathic vacuoles (CPV-I), from which nascent RNAs are extruded for cytoplasmic translation. By contrast, CHIKV ROs are poorly internalized, raising the question of their fate and functionality at the late stage of infection. Here, using <i>in situ</i> cryogenic-electron microscopy approaches, we investigate the outcome of CHIKV ROs and associated replication machinery in infecteJournal of virology<i>In situ</i> fate of Chikungunya virus replication organelles.PMC11265437FRM FDT202106013092ANR-10-INBS-05ANR-18-CE11-002Holy XNeyret ASpehner DCastellarin CBron PLai-Kee-Him JChee MFavier A-LBriant LLe Bihan OGirleanu MGirard JBernard Efalse<i>In situ</i> fate of Chikungunya virus replication organelles.Chikungunya virus (CHIKV) is a mosquito-borne pathogen responsible for an acute musculoskeletal disease in humans. Replication of the viral RNA genome occurs in specialized membranous replication organelles (ROs) or spherules, which contain the viral replication complex. Initially generated by RNA synthesis-associated plasma membrane deformation, alphavirus ROs are generally rapidly endocytosed to produce type I cytopathic vacuoles (CPV-I), from which nascent RNAs are extruded for cytoplasmic translation. By contrast, CHIKV ROs are poorly internalized, raising the question of their fate and functionality at the late stage of infection. Here, using <i>in situ</i> cryogenic-electron microscopy approaches, we investigate the outcome of CHIKV ROs and associated replication machinery in infecte2024-01-01T00:00:00Z2024 Jul2026-06-01T08:55:19.514Z2025-04-06T22:38:54.33ZS-EPMC112654373894058610.1128/jvi.00368-24