Fig. 4.
End-joining in XLF−/− B cells requires the Tudor domain, but not the BRCT domain, of 53BP1. 53BP1−/−XLF−/− B cells with single clonal integration of pMX-INV (Inv 26) cells were infected with pBMN-ihCD2-53BP1WT, pBMN-ihCD2-53BP1ΔBRCT, or pBMN-ihCD2-53BP1ΔBRCT. (A) Flow cytometry analysis for GFP expression in different cells with identical substrate integration treated with STI for 0, 2, or 4 d with or without ATM inhibitor. (B) Southern blot analysis with hCD4 probe of EcoRV+NcoI (Upper) and EcoRV (Lower) digested genomic DNA from the indicated v-abl–transformed B cells treated with STI571 with or without ATM inhibitor as indicated.