Genome-wide analysis of RB and p130 binding in human diploid fibroblasts

The action of RB as a tumor suppressor has been difficult to define, in part, due to the redundancy of the related proteins p107 and p130. By coupling advanced RNAi technology with a genome wide analysis of gene expression and RB chromatin binding, we identified a unique and specific activity of RB in repressing DNA replication as cells exit the cell cycle into senescence, a tumor suppressive program. Binding of RB was examined in growing, quiescent, senescent or senescent cells lackign RB. Binding of p130 was examined in quiescent or senescent cells in the presence or absence of RB. Libraries were prapered from DNA co-precipiated with RB or p130 specific antibodies or from mock (beads-only) immunoprecipiates.