UV-induced fragmentation of Cajal bodies.
The morphology and composition of subnuclear organelles, such as Cajal bodies (CBs), nucleoli, and other nuclear bodies, is dynamic and can change in response to a variety of cell stimuli, including stress. We show that UV-C irradiation disrupts CBs and alters the distribution of a specific subset of CB components. The effect of UV-C on CBs differs from previously reported effects of transcription inhibitors. We demonstrate that the mechanism underlying the response of CBs to UV-C is mediated, at least in part, by PA28gamma (proteasome activator subunit gamma). The presence of PA28gamma in coilin-containing complexes is increased by UV-C. Overexpression of PA28gamma, in the absence of UV-C treatment, provokes a similar redistribution of the same subset of CB components that respond to UV-C. RNA interference-mediated knockdown of PA28gamma attenuates the nuclear disruption caused by UV-C. These data demonstrate that CBs are specific nuclear targets of cellular stress-response pathways and identify PA28gamma as a novel regulator of CB integrity.
Cioce
Mario
M
Gene Regulation and Expression Division, University of Dundee, Dundee DD1 5EH, Scotland, UK.
Boulon
Séverine
S
Matera
A Gregory
AG
Lamond
Angus I
AI
D000818:Animals; D001324:Autoantigens / Q000378:metabolism* / Q000528:radiation effects; D019556:COS Cells; D002467:Cell Nucleus / Q000378:metabolism / Q000528:radiation effects*; D002522:Chlorocebus aethiops; D020541:Coiled Bodies / Q000378:metabolism / Q000528:radiation effects* / Q000648:ultrastructure; D006367:HeLa Cells; D006801:Humans; D046912:Multiprotein Complexes / Q000528:radiation effects; D009687:Nuclear Proteins / Q000378:metabolism / Q000528:radiation effects*; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism* / Q000528:radiation effects; D021381:Protein Transport / Q000528:radiation effects; D014162:Transfection; D014466:Ultraviolet Rays; D015854:Up-Regulation
D001324:Autoantigens; C099558:Ki antigen; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; C068921:p80-coilin; D046988:Proteasome Endopeptidase Complex