PRMT5 and growth control. (A) Effect of PRMT5 and E2F-1 siRNA on cell growth. PRMT5 (P), E2F-1 (E) or control (C) siRNA (25 nM) was transfected as indicated into U2OS cells and cells counted (in triplicate) after 48, 72 and 96 h (i). The level of PRMT5 and E2F-1 in siRNA-treated cells is shown (ii) and the doubling time (iii) and growth rate (iv) was calculated from the results in (i). (B) U2OS cells were transfected with PRMT5 (P), E2F-1 (E) or control (C) or (25 nM) as indicated, and colony growth measured at 10 days after staining with crystal violet. (C) U2OS cells were transfected with expression vectors encoding WT E2F-1 (WT) or the KK and KKK mutant derivatives as indicated, and cells counted (in triplicate) at 48, 72 and 96 h (i). The level of ectopic E2F-1 protein is shown in (ii), which was adjusted for equivalent expression.