Fig. 4.

LigIII is required for the viability and efficient DNA replication of the LigI-deficient cells. a Effects of LigI-depletion on the plating efficiency in HeLa, MCF7, and U2OS cells following lentiviral transduction with a LIGI shRNA (shLigI) were compared to the respective control (shCTL) cell populations. b The control shRNA (shCTL) or LIGI shRNA (shLigI) molecules were introduced by lentiviral transduction of HeLa cells expressing either a control (CTL), LIGIII (LigIII^KD), XRCC1 (XRCC1^KD), or PARP1 (PARP1^KD) shRNA from the pEBV episomal plasmid. The plating efficiency of the cell populations expressing the indicated pair of shRNAs was compared to that of the HeLa^CTL-shCTL cells expressing the control shRNAs. c The LigI, LigIII, XRCC1, and PARP1 protein levels were analyzed by Western blotting. d Two days post-infection, LigI-depletion was verified at the cellular level by immunofluorescence (red) and the replicating cells were detected by BrdU incorporation (green). e Percentages of BrdU-positive cells detected in the indicated HeLa cells populations following a 30-min BrdU pulse. The values ± SD represent the mean of two experiments for which at least 150 nuclei per experiment were scored