Figure 8 .

Divergence and conservation of RB regulon. A total of 2310 identifiable human orthologs of Rbf1 targets were compared with RB targets in growing (A), quiescent (B), and senescent (C) cells and p130 targets in quiescent (D) and senescent (E) cells. The overlaps in (A), (B), and (C) were further compared with each other (F) and the overlaps in (D) and (E) were compared with each other (G). Comparison of the total genes in (F) and (G) with each other (H), shows that most of the targets of Rbf1 and RB, as well as Rbf1 and p130, are the same. In all overlaps in A-E, GO terms DNA Replication, Cell Cycle, DNA Repair, and Chromatin Modification were enriched, indicating that these genes may form a conserved ancient regulon of RB proteins. The overlap of human homologs of Rbf1 targets in Drosophila embryos and RB and p130 targets in human cell culture suggests that many genes have retained regulation by RB proteins since divergence of these organisms. Other categories of genes may represent divergence of RB family function, or context-dependent differences in binding. Human homologs for Rbf1 targets were compared with published RB and p130 targets in growing, quiescent and senescent human lung fibroblasts (Chicas et al. 2010).