Figure 6.

RB S838/T841 phosphorylation regulates chromatin dynamics upon T-cell receptor signaling.A jurkat cells were stimulated by T-cell receptor cross-linking as indicated. Cells were fixed and lysed to obtain chromatin fractions. Chromatin was sonicated for one to three cycles. Protein–DNA cross-links were reversed, and DNA was purified and analyzed on a 3% agarose gel. DNA was stained with ethidium bromide and visualized on a Chemi Doc. The high-molecular-weight DNA band indicated by the arrow was quantified on Image Lab, and intensity is expressed as a percentage of the total lane normalized within each group. B, untransduced Jurkat cells were PBS or TCR cross-linked as described in A. Chromatin fragmentation is shown. C, percent high-molecular-weight DNA quantities were averaged and graphed (n = 3, ∗ indicates p < 0.05, two-way ANOVA with Sidak’s multiple comparisons test). D, lentiviral transduced Jurkat cells were stimulated by T-cell receptor cross-linking, fixed, and lysed to obtain chromatin fractions. Chromatin was sonicated for increasing number of cycles and analyzed as in A. E, the high-molecular-weight band indicated by the arrow was quantified, averaged, and graphed, (n = 3, ∗ indicates p < 0.05, Two-way ANOVA with Sidak’s multiple comparisons test).