FIG. 4.

Nuclear affinity of partially phosphorylated pRb. U2-OS cells grown on coverslips were transfected with the indicated plasmids and CD20 expression plasmid, subjected to indirect immunofluorescence with anti-CD20 antibody, and then mock treated or subjected to low-salt extraction prior to indirect immunofluorescence with anti-pRb antibody. The mean and standard error of the mean from three independent experiments are shown. For each experimental sample, 50 CD20-positive cells were analyzed.