7.5 Â 10 5 Daudi cells or 5 Â 10 5 SK-N cells were seeded into 12-well plates 24 h before transfection. Twoand-a-half micrograms of siRNA was transfected to Daudi or SK-N cells using Lipofectamine 2000 (Invitrogen) to examine endogenous expression pattern of CD200 following silencing SF2/ASF. Two-and-a-half micrograms of siRNA, together with 10 mg of the alternative splicing construct DNA, was transfected to Daudi or SK-N cells by electroporation to detect exogenous expression pattern of CD200 following silencing SF2/ASF. The cells were harvested 48 h posttransfection. Total RNA and protein were then extracted.