Primase couples leading- and lagging-strand DNA synthesis from oriC.

摘要: Coupling of leading- and lagging-strand DNA synthesis at replication forks formed Escherichia coli oriC has been studied in vitro using a system reconstituted with purified proteins. At low concentrations primase (8 nM), the major products were multigenome-length molecules, generated by rolling circle-type mechanism, unit-length molecules. Rolling circle was inhibited high (80 nM) half-unit-length leading strands distinct population short Okazaki fragments. concentrations, an asymmetric mode occurred. Each strand made independently initiation could occur outside oriC. occurred exclusively two coupled proceeded bidirectionally around plasmid. Presumably, primase, DnaB (the fork helicase) unwound plasmid before form, to sites other than On hand, resulted successful capture helicase formation capable coordinated synthesis.