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Role of architectural elements in combinatorial regulation of initiation of DNA replication in Escherichia coli
Author(s) -
Polaczek Piotr,
Kwan Kelvin,
Liberles David A.,
Campbell Judith L.
Publication year - 1997
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.1997.5701931.x
Subject(s) - biology , dnaa , dna , seqa protein domain , origin of replication , dna replication , host factor , dna binding protein , genetics , binding site , methylation , gene , microbiology and biotechnology , transcription factor
Bending of DNA is a prerequisite of site‐specific recombination and gene expression in many regulatory systems involving the assembly of specific nucleoprotein complexes. We have investigated how the uniquely clustered Dam methylase sites, GATCs, in the origin of Escherichia coli replication ( oriC ) and their methylation status modulate the geometry of oriC and its interaction with architectural proteins, such as integration host factor (IHF), factor for inversion stimulation (Fis) and DnaA initiator protein. We note that 3 of the 11 GATC sites at oriC are strategically positioned within the IHF protected region. Methylation of the GATCs enhances IHF binding and alters the IHF‐induced bend at oriC . GATC motifs also contribute to intrinsic DNA curvature at oriC and the degree of bending is modulated by methylation. The IHF‐induced bend at oriC is further modified by Fis protein and IHF affinity for its binding site may be impaired by protein(s) binding to GATCs within the IHF site. Thus, GATC sites at oriC affect the DNA conformation and GATCs, in conjunction with the protein‐induced bends, are critical cis ‐acting elements in specifying proper juxtapositioning of initiation factors in the early steps of DNA replication.