UVA irradiation induces relocalisation of the DNA repair protein hOGG1 to nuclear speckles.
The DNA glycosylase hOGG1 initiates base excision repair (BER) of oxidised purines in cellular DNA. Using confocal microscopy and biochemical cell fractionation experiments we show that, upon UVA irradiation of human cells, hOGG1 is recruited from a soluble nucleoplasmic localisation to the nuclear matrix. More specifically, after irradiation, hOGG1 forms foci colocalising with the nuclear speckles, organelles that are interspersed between chromatin domains and that have been associated with transcription and RNA-splicing processes. The use of mutant forms of hOGG1 unable to bind the substrate showed that relocalisation of hOGG1 does not depend on the recognition of the DNA lesion by the enzyme. The recruitment of hOGG1 to the nuclear speckles is prevented by the presence of antioxidant compounds during UVA irradiation, implicating reactive oxygen species as signals for the relocalisation of hOGG1. Furthermore, APE1, the second enzyme in the BER pathway, is also present in nuclear speckles in UVA-irradiated cells. The recruitment of DNA repair proteins to nuclear speckles after oxidative stress implicates these organelles in the cellular stress response.
Campalans
Anna
A
Département de Radiobiologie et Radiopathologie, Commissariat à l'Energie Atomique, UMR 217 CNRS/CEA, 18 route du Panorama, 92265 Fontenay aux Roses, France.
Amouroux
Rachel
R
Bravard
Anne
A
Epe
Bernd
B
Radicella
J Pablo
JP
D001692:Biological Transport / Q000528:radiation effects; D002467:Cell Nucleus / Q000201:enzymology* / Q000648:ultrastructure*; D045647:DNA Glycosylases / Q000235:genetics / Q000378:metabolism*; D004260:DNA Repair / Q000502:physiology*; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D049452:Green Fluorescent Proteins / Q000235:genetics; D006151:Guanosine / Q000031:analogs & derivatives / Q000096:biosynthesis / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D017382:Reactive Oxygen Species / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D014158:Transcription, Genetic; D014466:Ultraviolet Rays
D017382:Reactive Oxygen Species; D011993:Recombinant Fusion Proteins; D006151:Guanosine; D049452:Green Fluorescent Proteins; C046215:8-hydroxyguanosine; D045647:DNA Glycosylases; C479058:oxoguanine glycosylase 1, human; C085108:APEX1 protein, human; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase