CtBP1 is essential for survival and proliferation. (A) Survival and proliferation curves of HeLa cells transduced with shRNA against CtBP1 (CtBP1i), CtBP1/CtBP2 (CtBPi), FANCA (FANCAi), or FANCD2 (FANCD2i). The percentages of living cells were scored via calcein-AM staining on each day post-transduction. Living cells were scored with a FACSCalibur cytometer (BD Biosciences) and the percentage of live cells in each sample was determined with CellQuest Pro software (BD Biosciences, Mississauga, ON). (B) Representative metaphase spread of HeLa cells transduced with shRNA against CtBP1 (CtBP1i), FANCA (FANCAi), or FANCD2 (FANCD2i) following a 16 hours exposure to 150 nM MMC. Arrows indicate chromatid-type breakage and radial rejoining. (C) Numbers of chromosomal breaks and aberrations per metaphase nucleus identified in CtBP1-depleted (CtBP1i), FANCA-depleted (FANCAi), and FANCD2-depleted (FANCD2i) HeLa cells. Each experiment was performed a minimum of 3 times. To evaluate chromosomal abnormalities, 25 metaphase nuclei were analyzed per experiment with a Carl Zeiss Axio Imager M2 microscope equipped with an Axiocam MRm camera and Axiovision Rel.4.8 software (100× magnification). Values represent the means ± SEM. *P ≤ .05; **P ≤ .01 vs control shRNA scrambled transduced cells.