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Mechanistic studies of initiator–initiator interaction and replication initiation
Author(s) -
Lu YaBin,
Datta Hirock J.,
Bastia Deepak
Publication year - 1998
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/17.17.5192
Subject(s) - dnaa , library science , plasmid , biology , origin of replication , genetics , computer science , dna
Unlike the chromosome of Escherichia coli that needs only one replication initiator protein (origin recognition protein) called DnaA, many plasmid replicons require dual initiators: host‐encoded DnaA and a plasmid‐encoded origin recognition protein, which is believed to be the major determinant of replication control. Hitherto, the relative mechanistic roles of dual initiators in DNA replication were unclear. Here, we present the first evidence that DnaA communicates with the plasmid‐encoded π initiator of R6K and contacts the latter at a specific N‐terminal region. Without this specific contact, productive unwinding of plasmidori γ and replication is abrogated. The results also show that DnaA performs different roles in host and plasmid replication as revealed by the finding that the ATP‐activated form of DnaA, while indispensable for oriC replication, was not required for R6K replication. We have analyzed the accessory role of the DNA bending protein, integration host factor (IHF), in promoting initiator–origin interaction and have found that IHF significantly enhances the binding of DnaA to its cognate site. Collectively, the results further advance our understanding of replication initiation.