Control of plasmid DNA replication by iterons: no longer paradoxical.

摘要: Replication origins of a family bacterial plasmids have multiple sites, called iterons, for binding plasmid-specific replication initiator protein. The iteron–initiator interactions are essential plasmid as well inhibition over-replication. increases with copy number and eventually shuts off completely. mechanism appears to be handcuffing, the coupling via iteron-bound initiators that block origin function. probability trans-reaction such handcuffing is expected increase diminish in cell volume, explaining how can maintained growing cell. Control also exerted at level synthesis activation by chaperones. We propose active promote initiation overcoming but dominates when reaches threshold. Handcuffing should ultrasensitive number, negative control iterons stringent (switch-like).