title: UVC-induced stress granules in mammalian cells.
abstract: Stress granules (SGs) are well characterized cytoplasmic RNA bodies that form under various stress conditions. We have observed that exposure of mammalian cells in culture to low doses of UVC induces the formation of discrete cytoplasmic RNA granules that were detected by immunofluorescence staining using antibodies to RNA-binding proteins. UVC-induced cytoplasmic granules are not Processing Bodies (P-bodies) and are bone fide SGs as they contain TIA-1, TIA-1/R, Caprin1, FMRP, G3BP1, PABP1, well known markers, and mRNA. Concomitant with the accumulation of the granules in the cytoplasm, cells enter a quiescent state, as they are arrested in G1 phase of the cell cycle in order to repair DNA damages induced by UVC irradiation. This blockage persists as long as the granules are present. A tight correlation between their decay and re-entry into S-phase was observed. However the kinetics of their formation, their low number per cell, their absence of fusion into larger granules, their persistence over 48 hours and their slow decay, all differ from classical SGs induced by arsenite or heat treatment. The induction of these SGs does not correlate with major translation inhibition nor with phosphorylation of the α subunit of eukaryotic translation initiation factor 2 (eIF2α). We propose that a restricted subset of mRNAs coding for proteins implicated in cell cycling are removed from the translational apparatus and are sequestered in a repressed form in SGs.
authors.affiliation: Centre de recherche, Institut universitaire en santé mentale de Québec, Département de psychiatrie et de neurosciences, Université Laval, Québec, PQ, Canada.
authors.forename: Mohamed Taha
authors.initials: MT
authors.lastname: Moutaoufik
authors.affiliation: Centre de recherche, Institut universitaire en santé mentale de Québec, Département de psychiatrie et de neurosciences, Université Laval, Québec, PQ, Canada.
authors.forename: Rachid
authors.initials: R
authors.lastname: El Fatimy
authors.affiliation: Centre de recherche du CHU de Québec. Département de biologie moléculaire, biochimie médicale et pathologie, Université Laval, Québec, PQ, Canada.
authors.forename: Hassan
authors.initials: H
authors.lastname: Nassour
authors.affiliation: Centre de recherche du CHU de Québec. Département de biologie moléculaire, biochimie médicale et pathologie, Université Laval, Québec, PQ, Canada.
authors.forename: Cristina
authors.initials: C
authors.lastname: Gareau
authors.affiliation: Centre de recherche, Institut universitaire en santé mentale de Québec, Département de psychiatrie et de neurosciences, Université Laval, Québec, PQ, Canada.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Lang
authors.affiliation: Laboratoire de génétique cellulaire et du développement, Département de biologie moléculaire, biochimie médicale et pathologie, Université Laval, Québec, PQ, Canada.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Tanguay
authors.affiliation: Centre de recherche du CHU de Québec. Département de biologie moléculaire, biochimie médicale et pathologie, Université Laval, Québec, PQ, Canada.
authors.forename: Rachid
authors.initials: R
authors.lastname: Mazroui
authors.affiliation: Centre de recherche, Institut universitaire en santé mentale de Québec, Département de psychiatrie et de neurosciences, Université Laval, Québec, PQ, Canada.
authors.forename: Edouard W
authors.initials: EW
authors.lastname: Khandjian
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D049109:Cell Proliferation / Q000528:radiation effects; D003593:Cytoplasm / Q000378:metabolism / Q000528:radiation effects*; D004247:DNA / Q000096:biosynthesis; D004307:Dose-Response Relationship, Radiation; D051379:Mice; D041681:NIH 3T3 Cells; D014466:Ultraviolet Rays
chemical_list: D015415:Biomarkers; D004247:DNA