Capture of extranuclear DNA at fission yeast double-strand breaks.
Proper repair of DNA double-strand breaks (DSBs) is necessary for the maintenance of genomic integrity. Here, a new simple assay was used to study extrachromosomal DSB repair in Schizosaccharomyces pombe. Strikingly, DSB repair was associated with the capture of fission yeast mitochondrial DNA (mtDNA) at high frequency. Capture of mtDNA fragments required the Lig4p/Pku70p nonhomologous end-joining (NHEJ) machinery and its frequency was highly increased in fission yeast cells grown to stationary phase. The fission yeast Mre11 complex Rad32p/Rad50p/Nbs1p was also required for efficient capture of mtDNA at DSBs, supporting a role for the complex in promoting intermolecular ligation. Competition assays further revealed that microsatellite DNA from higher eukaryotes was preferentially captured at yeast DSBs. Finally, cotransformation experiments indicated that, in NHEJ-deficient cells, capture of extranuclear DNA at DSBs was observed if homologies--as short as 8 bp--were present between DNA substrate and DSB ends. Hence, whether driven by NHEJ, microhomology-mediated end-joining, or homologous recombination, DNA capture associated with DSB repair is a mutagenic process threatening genomic stability.
Decottignies
Anabelle
A
Cellular Genetics, Christian de Duve Institute of Cellular Pathology, Catholic University of Louvain, Avenue Hippocrate 74+3, 1200 Brussels, Belgium. anabelle.decottignies@gece.ucl.ac.be
D001483:Base Sequence; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism; D019295:Computational Biology; D004249:DNA Damage / Q000235:genetics*; D000072481:DNA Ligase ATP; D011088:DNA Ligases / Q000235:genetics; D017931:DNA Primers; D004260:DNA Repair / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D005090:Exodeoxyribonucleases; D016681:Genome, Fungal / Q000235:genetics*; D018895:Microsatellite Repeats / Q000235:genetics; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D016296:Mutagenesis / Q000235:genetics*; D012568:Schizosaccharomyces / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA
D002868:Chromosomal Proteins, Non-Histone; D017931:DNA Primers; D004272:DNA, Mitochondrial; C478035:Nbs1 protein, S pombe; C480032:Rad50 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; C400810:ura4 protein, S pombe; D005090:Exodeoxyribonucleases; C092453:Mre11 protein, S pombe; D011088:DNA Ligases; D000072481:DNA Ligase ATP