KINETIC ASPECTS OF CONTROL OF PLASMID REPLICATION BY ANTISENSE RNA

Plasmids are replicating DNA molecules that are present in defined num bers of copies per cell. They encode systems that control their replic ation such that given steady-state values for their copy numbers are m aintained. This is a special type of control, since it requires the ge nome to measure its concentration continuously and adjust its rate of replication to parallel the rate of growth of the cell mass. In this r eview we discuss the quantitative kinetic properties of copy-number co ntrol of the R1 plasmid, in which the control device is an antisense R NA that controls the synthesis of a protein that is rate-limiting for replication of the plasmid.