The mAbs do not inhibit premRNA transcription, cell cycle progression, cell proliferation and do not induce apoptosis. (A) U2OS cells electroporated but without antibodies (UT elec), electroporated and treated with α-amanitin (α-ama), electroporated with a control antibody binding to bacterial MBP (anti-MBP), or electroporated with the mAbs recognizing specifically RPB1, TAF10, or TBP (anti-RPB1, anti-TAF10, or anti-TBP). 24 h after electroporation, total RNA was isolated, and the expression of Pol I, Pol II, and Pol III genes was analyzed by RT-qPCR. Pol III transcripts were used for normalization. Newly synthesized RNA of the indicated genes was quantified with validated primer pairs (Table S2). The histograms correspond to the mean values obtained with three independent experiments. (B) The mean values of the three independent experiments shown in A are represented as a heatmap reflecting unchanged relative expression in black, up-regulation in green, and down-regulation in red. (C) U2OS cells were electroporated as in A, and cell cycle progression was monitored by propidium iodide staining and FACS analysis 24 or 48 h after electroporation. The cell cycle phases were normalized to cells electroporated without antibody. (D) U2OS cells were electroporated as in A, and their capacity of proliferation was monitored 24 h after transduction by EdU incorporation and FACS. The electroporated cells without the addition of antibody were used as control. The color code is as in A. (E) The cells were treated as in A, except an apoptosis test was performed 24 h after electroporation. Apoptosis induced by the addition of 10 µM H₂O₂ was taken as reference (100%). In each panel, the error bars represent the biological SD obtained from three independent replicates. UT, untreated cells.