RPA and Rad51 constitute a cell intrinsic mechanism to protect the cytosol from self DNA

• Published in: Nature communications Vol. 7; no. 1; p. 11752
• Main Authors: Wolf, Christine, Rapp, Alexander, Berndt, Nicole, Staroske, Wolfgang, Schuster, Max, Dobrick-Mattheuer, Manuela, Kretschmer, Stefanie, König, Nadja, Kurth, Thomas, Wieczorek, Dagmar, Kast, Karin, Cardoso, M. Cristina, Günther, Claudia, Lee-Kirsch, Min Ae
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 27.05.2016; Nature Publishing Group; Nature Portfolio
• Subjects: 13; 13/1; 13/106; 13/109; 13/21; 13/31; 13/44; 13/51; 13/56; 13/89; 14; 14/19; 14/28; 14/33; 14/34; 14/35; 14/56; 140/125; 38; 38/39; 38/77; 38/89; 38/91; 631/250/256; 631/250/38; 631/337/1427; 631/337/151; Acids; Cells, Cultured; Cytosol - metabolism; Deoxyribonucleic acid; DNA; DNA damage; DNA, Single-Stranded - genetics; DNA, Single-Stranded - metabolism; Exodeoxyribonucleases - genetics; Exodeoxyribonucleases - metabolism; Fibroblasts - cytology; Fibroblasts - metabolism; HEK293 Cells; HeLa Cells; Humanities and Social Sciences; Humans; Interferon Type I - metabolism; Lupus; multidisciplinary; Mutation; Pathogenesis; Phosphoproteins - genetics; Phosphoproteins - metabolism; Protein Binding; Proteins; Rad51 Recombinase - genetics; Rad51 Recombinase - metabolism; Replication Protein A - genetics; Replication Protein A - metabolism; RNA Interference; Science; Science (multidisciplinary); Tumor Suppressor Protein p53 - metabolism; Germany
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms11752

Immune recognition of cytosolic DNA represents a central antiviral defence mechanism. Within the host, short single-stranded DNA (ssDNA) continuously arises during the repair of DNA damage induced by endogenous and environmental genotoxic stress. Here we show that short ssDNA traverses the nuclear membrane, but is drawn into the nucleus by binding to the DNA replication and repair factors RPA and Rad51. Knockdown of RPA and Rad51 enhances cytosolic leakage of ssDNA resulting in cGAS-dependent type I IFN activation. Mutations in the exonuclease TREX1 cause type I IFN-dependent autoinflammation and autoimmunity. We demonstrate that TREX1 is anchored within the outer nuclear membrane to ensure immediate degradation of ssDNA leaking into the cytosol. In TREX1-deficient fibroblasts, accumulating ssDNA causes exhaustion of RPA and Rad51 resulting in replication stress and activation of p53 and type I IFN. Thus, the ssDNA-binding capacity of RPA and Rad51 constitutes a cell intrinsic mechanism to protect the cytosol from self DNA. A central antiviral defence is immune recognition of cystolic DNA. Here the authors show that RPA and RAD51, in cooperation with TREX1, function to protect the cytosol from self-DNA.