Base excision repair of 8-oxoG in dinucleosomes

Hervé Menoni (1) , Manu Shubhdarshan Shukla (1) , Véronique Gerson (2) , Stefan Dimitrov (3) , Dimitar Angelov (1)

1 LBMC - Laboratoire de Biologie Moléculaire de la Cellule
2 Biologie moléculaire et cellulaire de la différenciation
3 INSERM U823 - Institut d'oncologie/développement Albert Bonniot de Grenoble

In this work we have studied the effect of chromatin structure on the base excision repair (BER) efficiency of 8-oxoG. As a model system we have used precisely positioned dinucleosomes assembled with linker histone H1. A single 8-oxoG was inserted either in the linker or the core particle DNA within the dinucleosomal template. We found that in the absence of histone H1 the glycosylase OGG1 removed 8-oxoG from the linker DNA and cleaved DNA with identical efficiency as in the naked DNA. In contrast, the presence of histone H1 resulted in close to 10-fold decrease in the efficiency of 8-oxoG initiation of repair in linker DNA independently of linker DNA length. The repair of 8-oxoG in nucleosomal DNA was very highly impeded in both absence and presence of histone H1. Chaperone-induced uptake of H1 restored the efficiency of the glycosylase induced removal of 8-oxoG from linker DNA, but not from the nucleosomal DNA. We show, however, that removal of histone H1 and nucleosome remodelling are both necessary and sufficient for an efficient removal of 8-oxoG in nucleosomal DNA. Finally, a model for BER of 8-oxoG in chromatin templates is suggested.

Domaines: Biochimie, Biologie Moléculaire

Hervé Menoni, Manu Shubhdarshan Shukla, Véronique Gerson, Stefan Dimitrov, Dimitar Angelov. Base excision repair of 8-oxoG in dinucleosomes. Nucleic Acids Research, 2011, 40 (2), pp.692-700. ⟨ensl-00807713⟩