Figure 7.

Model illustrating cooperation within the cell-cycle quiescence regulatory network. Genetic analyses suggest that at least four genetically distinct pathways collaborate to control cell cycles during development. As described in the text, three pathways mediated by LIN-35/pRb, UBC-25/UBE2Q2, and CKI-1/p27 regulate cye-1/cyclin E activity at the level of transcription, protein stability and activity, respectively. The mechanism through which B0393.6/RNF182 controls cell cycles remains undefined.