Fig. 2. Usp7 knockout (KO)-mediated negative regulation of H2B ubiquitination during retinoic acid (RA)-induced neuronal differentiation. (A) The histone H2B monoubiquitination (H2Bub1) protein expression levels in the control and Usp7 KO P19 cells during RA-induced neuronal differentiation analyzed by Western blot. Differentiated samples were collected on the indicated days. The protein expression of H2Bub1 and total H2B were analyzed by Western blot. (B) RA-induced neuronal differentiation in P19 cells. Differentiated samples were collected on the indicated days and the protein expression of Usp7 were analyzed by Western blot. (C) The messenger RNA (mRNA) expression of Usp7 in control P19 cells was estimated by real-time polymerase chain reaction during RA-induced differentiation. Error bars were derived from three independent experiments. N=3. ***p<0.001.