Expression of cell cycle markers modulated by U0126. RD cells were treated with 10 μM U0126 for the times indicated. (A) whole cell lysates from untreated (-) or U0126-treated cells (+) were separated on 12% SDS-PAGE and analysed by immunoblotting with specific antibodies for the proteins indicated. α-tubulin expression shows equal loading. pRb was analysed on a filter from 7% SDS-PAGE. Densitometric analysis of bands provided quantification expressed as the ratio of the amount of cell cycle protein versus α-tubulin amount. (B) Graph shows the quantification of the results presented in A expressed as a fold increase of the indicated cell cycle protein in the U0126 sample over the untreated sample at the time points examined. (C) Northern blot from total RNA of untreated (-) and U0126-treated cells (+). Loading was tested by reprobing the same filter with GAPDH. Densitometric analysis of bands provided quantification as the ratio of the amount of mRNA cell cycle protein versus mRNA GAPDH amount. The data shown are representative of two independent experiments.