A robust network of double-strand break repair pathways governs genome integrity during C. elegans development.
To preserve genomic integrity, various mechanisms have evolved to repair DNA double-strand breaks (DSBs). Depending on cell type or cell cycle phase, DSBs can be repaired error-free, by homologous recombination, or with concomitant loss of sequence information, via nonhomologous end-joining (NHEJ) or single-strand annealing (SSA). Here, we created a transgenic reporter system in C. elegans to investigate the relative contribution of these pathways in somatic cells during animal development. Although all three canonical pathways contribute to repair in the soma, in their combined absence, animals develop without growth delay and chromosomal breaks are still efficiently repaired. This residual repair, which we call alternative end-joining, dominates DSB repair only in the absence of NHEJ and resembles SSA, but acts independent of the SSA nuclease XPF and repair proteins from other pathways. The dynamic interplay between repair pathways might be developmentally regulated, because it was lost from terminally differentiated cells in adult animals. Our results demonstrate profound versatility in DSB repair pathways for somatic cells of C. elegans, which are thus extremely fit to deal with chromosomal breaks.
Pontier
Daphne B
DB
Hubrecht Institute, Koninklijke Nederlandse Akademie van Wetenschappen, University Medical Centre Utrecht, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands.
Tijsterman
Marcel
M
D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000254:growth & development; D029742:Caenorhabditis elegans Proteins / Q000235:genetics; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair / Q000235:genetics / Q000502:physiology*; D018509:DNA, Helminth / Q000235:genetics* / Q000378:metabolism; D017930:Genes, Reporter; D049751:Genome, Helminth; D007814:Larva; D008957:Models, Genetic; D016133:Polymerase Chain Reaction; D011993:Recombinant Fusion Proteins / Q000502:physiology; D017384:Sequence Deletion; D019076:Transgenes / Q000235:genetics
C528463:BRC-1 protein, C elegans; D029742:Caenorhabditis elegans Proteins; D018509:DNA, Helminth; D011993:Recombinant Fusion Proteins