VRK1 knockdown results in G2–M arrest, BAF deregulation, and nuclear lamina defects. A, Cell-cycle distributions were determined by flow cytometric analyses in U251MG VRK2-low and VRK-high cells in the presence or absence of 1 μg/mL doxycycline for 7 days. B, Cell-cycle distributions were determined by flow cytometric analyses in HAP1 VRK2-null and parental cells 5 days after VRK1 CRISPR knockdown. C, Immunoblots of U251MG VRK2-low and VRK2-high cells treated with or without doxycycline for 3, 5, and 7 days. D, Immunoblots of HAP1 VRK2-null and parental cells knocked out with VRK1 or intron-cutting control guides for 3, 5, and 7 days. E, U251MG VRK2-low and VRK2-high cells were treated with or without doxycycline for 5 days and immunostained for lamin B (green) and Hoechst (blue) and imaged by high-content imaging. Scale bar, 50 μm. F, Quantification of abnormal nuclear envelope from E. G, Quantification of cells arrested in mitosis from E. *, P < 0.01; ****, P < 0.0001; ns, not significant (two-tailed t test).