Contributors: Thomas, Frank; Institut de biologie structurale (IBS - UMR 5075); Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG); Direction de Recherche Fondamentale (CEA) (DRF (CEA)); Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)); Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA); Institut de Biologie Intégrative de la Cellule (I2BC); Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS); LabEx GRAL (Ecoles Universitaires de Recherche); Financement par le programme radiobiologie du CEA; M4D imaging platform of the Grenoble Instruct-ERIC Center (ISBG: UMS 3518 CNRS-CEA-UGA-EMBL); Partnership for Structural Biology (PSB); University Grenoble Alpes graduate school (Ecoles Universitaires de Recherche); ANR-20-CE11-0013,STABLE-FP,Nouvelle génération de protéines fluorescentes ultrastables pour la microscopie quantitative super-résolution(2020); ANR-22-CE11-0029,NUC-STRESS,Une étude multi-échelle des changements architecturaux et de dynamique du nucléoïde induits par le stress(2022); ANR-17-EURE-0003,CBH-EUR-GS,CBH-EUR-GS(2017); ANR-10-INBS-0005,FRISBI,Infrastructure Française pour la Biologie Structurale Intégrée(2010); ANR-10-LABX-0049,GRAL,Grenoble Alliance for Integrated Structural Cell Biology(2010)
نبذة مختصرة : Bacteria have developed a wide range of strategies to respond to stress, one of which is the rapid large-scale reorganization of their nucleoid. Nucleoid associated proteins (NAPs) are believed to be major actors in nucleoid remodeling, but the details of this process remain poorly understood. Here, using the radiation resistant bacterium D. radiodurans as a model, and advanced fluorescence microscopy, we examined the changes in nucleoid morphology and volume induced by either entry into stationary phase or exposure to UV-C light, and characterized the associated changes in mobility of the major NAP in D. radiodurans, the heat-unstable (HU) protein. While both types of stress induced nucleoid compaction, HU diffusion was reduced in stationary phase cells, but was instead increased following exposure to UV-C, suggesting distinct underlying mechanisms. Furthermore, we show that UV-C-induced nucleoid remodeling involves a rapid nucleoid condensation step associated with increased HU diffusion, followed by a slower decompaction phase to restore normal nucleoid morphology and HU dynamics, before cell division can resume. These findings shed light on the diversity of nucleoid remodeling processes in bacteria and underline the key role of HU in regulating this process through changes in its mode of assembly on DNA.
Processing Request
No Comments.