Interlocking of plasmid DNAs due to Lac repressor-operator interaction.
The presence of a single lac repressor binding sequence on plasmid DNAs is shown to mediate the formation of interlocked dimers in E. coli. The presence of both homo- and hetero-interlocked dimers suggests that the lac repressor complex can bring together randomly two plasmid DNA molecules to facilitate gyrase-mediated interlocking. The exclusive formation of multiply intertwined dimers also suggest that the lac repressor complex may bind simultaneously to a pair of replicated daughter plasmid molecules prior to their segregation. The formation of interlocked plasmid DNAs can be indicative of interaction between two DNA bound proteins in vivo.
Wu
H Y
HY
Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201.
Lau
K
K
Liu
L F
LF
D001483:Base Sequence; D004250:DNA Topoisomerases, Type II / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D007763:Lac Operon / Q000235:genetics*; D046911:Macromolecular Substances; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009875:Operator Regions, Genetic / Q000235:genetics*; D010957:Plasmids / Q000235:genetics*; D012097:Repressor Proteins / Q000378:metabolism*
D004269:DNA, Bacterial; D046911:Macromolecular Substances; D012097:Repressor Proteins; D004250:DNA Topoisomerases, Type II