Figure 1.

Progression permission model. (A) General logic for 1:1:1 coordination of cell growth, replication initiation and cell division. Note: in slow growth conditions, PCC development clearly precedes satisfaction of the growth requirement such that the two features operate in parallel. In fast growth conditions, it is less clear whether the growth input is independent of PCC development and/or feeds into development of the PCC. This ambiguity is indicated by the (^**); see text. (B) Development of the proposed PPC by integration of chromosome and divisome inputs.