TopBP1 Stabilizes BLM Protein to Suppress Sister Chromatid Exchange

Human TopBP1 plays essential roles in DNA replication and replication checkpoint control. In our recent paper “TopBP1 controls BLM protein level to maintain genome stability,” we provided evidence suggesting that TopBP1 has an unexpected role in suppressing sister chromatid exchange (SCE) and that this function is independent of its known activities in replication checkpoint control (Wang et al., 2013). In their Matters Arising (Blackford et al., 2015, this issue of Molecular Cell), Blackford et al.