A virtual protein-protein interaction screen. (A) 642 Drosophila putative cell cycle regulators were used as baits to query DroID, the Drosophila Interactions Database. Baits included hits from the two previous RNAi-based screens for cell cycle regulators along with a set of additional genes annotated as being involved in the cell cycle. The original interaction map was filtered to remove low confidence interactions (see Methods). The filtered map includes 473 of the bait proteins (red nodes), and 1843 interactors (blue nodes). 94.8% of the proteins are connected into one large network. (B) A subnetwork from (A) involving six members of the COP9 signalosome protein complex that was previously identified as a regulator of the G1/S transition. Signalosome components are shown as triangles while their interaction partners are circles. Proteins that were used as baits in the virtual protein-protein interaction screen are shown in red while their interaction partners are shown in blue.