FIGURE 2.

Proposed model for inhibition of RAD51‐dependent homologous recombination by SYCP3 is depicted. In the early stage of homologous recombination in SYCP3‐nonexpressing cells (left), the DNA double‐strand break ends are resected, resulting in generation of 3′ single‐stranded DNA (ssDNA) overhangs on both sides of the break. These overhangs are coated and stabilized by replication protein A (RPA). Next, BRCA2 directly binds RAD51 and recruits it to the double‐stranded DNA‐ssDNA junction, and promotes the loading of RAD51 onto ssDNA. This step is followed by displacement of RPA from ssDNA ends and assembly of the RAD51‐ssDNA filament, leading to strand invasion into an undamaged homologous DNA template. In SYCP3‐expressing cells (right), SYCP3 forms a complex with BRCA2 and impairs the recruitment of RAD51 to resected DNA double‐strand breaks, resulting in defective homologous recombination