A) U87 or A172 cells were infected with a control virus or a YAP1 expressing lentiviral construct. YAP1 expression was visualized by western blot for the V5 epitope tag. Quadruplicate cultures were counted after four days, and relative cell number is shown. B) YAP1 was knocked down by shRNA lentiviral infection in U87 or A172 cells. Endogenous YAP1 expression is shown by YAP1 western blot together with relative cell number after four days (quadruplicate cultures as in A). C) U87 cells with YAP1 overexpression or knockdown were assayed for growth in soft agar: 10,000 cells per well were plated for sh-lacZ and sh-YAP1, 5,000 cells per well for lacZ and YAP1. Average colony number and images of representative wells are shown. D) U87 cells were co-infected with lentiviral vectors expressing YAP1 (V5 epitope tagged) or lacZ and either the control Flag vector or one with 3×Flag Myt1 or Myt1l. Expression of Myt1, Myt1l and YAP1 was analyzed by western blot for the epitope tags, and HSP90 as a loading control is shown below. Quadruplicate cultures of each of the U87 lines were maintained for two serial passages and cell number after the first passage and cumulative cell number after two passages is shown (mean + sd). p-values were determined by Student’s T test (p < 0.01): # For Myt1 or Myt1 expressing lacZ versus control/lacZ, ^ for YAP1 expressing versus equivalent lacZ line. E) Control or shYAP1 infected U87 cells were injected orthotopically into nude mice and tumors imaged by MRI after three weeks. Average (+ s.d.) tumor volume is shown, together with representative images (red lines outline the tumors). For panels A-C and E, p-values were determined by Student’s T-test: * p < 0.05, ** p < 0.01, *** p < 0.001, *** p < 0.0001. Panels A, B and D show representative experiments that were repeated twice with similar results. The average and s.d. shown is based on replicates within a single experiment. Data for C and E are from single experiment, with average and s.d. shown based on replicates (6 wells each in C, and 8 mice each in E).