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. Author manuscript; available in PMC: 2011 Apr 19.
Published in final edited form as: Annu Rev Biochem. 2010;79:181–211. doi: 10.1146/annurev.biochem.052308.093131

Figure 1. Causes and Repair of Double-Strand DNA Breaks.

Figure 1

Physiologic and pathologic causes of double-strand breaks in mammalian somatic cells are listed at the top. During S and G2 of the cell cycle, homology-directed repair is common because the two sister chromatids are in close proximity, providing a nearby homology donor. Homology-directed repair includes homologous recombination (HR) and single-strand annealing (SSA). At any time in the cell cycle, double-strand breaks can be repaired by nonhomologous DNA end joining (NHEJ). Proteins involved in the repair pathways are listed.