Suppression of Ubc13 expression inhibits constitutive NF-κB signaling and cell survival of ABC-DLBCL cell. (A) Analysis of Ubc13 expression. OCI-Ly10 cells were infected with lentiviruses that express either shControl or shUbc13. The levels of Ubc13 protein in the infected cells were analyzed 7 days after infection by Western blotting with a Ubc13-specific Ab. The amount of total protein lysates loaded in each lane is indicated. (B) Effect of Ubc13 knockdown on constitutive NF-κB signaling in OCI-Ly10 cells. Expression of the indicated proteins was analyzed by Western blotting. (C) Viability of the infected OCI-Ly10 cells was measured by trypan blue exclusion assay at the indicated times after infection. (D) Apoptosis of the infected OCI-Ly10 cells at 9 days after infection was analyzed as described in “Analyses of cell viability, apoptosis, and cell-cycle progression.”