Fig. 4

POLR2A protein accumulation in KO neural tubes and NPCs. A, B Increased levels of hyper- and hypo-phosphorylated POLR2A protein (A; recognized by mAb 4H8) and total POLR2A protein (B; recognized by anti-N-terminal mAb F12) in e9.5 KO neural tubes and KO NPCs according to immunoblotting. C,D Increased levels of S2-phosphorylated POLR2A (C; recognized by mAb E1Z3G) and S5-phosphorylated POLR2A (D; recognized by mAb D9N5I) in e9.5 KO neural tubes and KO NPCs. Representative immunoblots are shown. Bar graphs (mean ± SD) in the lower panels from A to D summarize the results of 3–5 independent experiments for each of these panels. E Polr2a mRNA levels of KO and WT e9.5 neural tubes were similar according to RT-qPCR. F Polr2a mRNA levels in the KO NPCs were lower than the WT counterparts. In E and F, the ratios (means ± SD) of signals of the testing molecules versus that of β-actin are shown. Data were analyzed by paired two-way Student’s t tests. *p < 0.05; ***p < 0.001