DNA looping alters local DNA conformation during transcription.
The effect of protein-mediated DNA looping on local DNA conformation during active transcription was studied using the lac repressor-operator system. Our results suggest that lac repressor-mediated DNA looping within a plasmid DNA molecule containing two lac repressor binding sequences in vivo effectively separates plasmid DNA into two topological domains. Supercoils generated by transcription within each topological domain can be rapidly removed by DNA topoisomerase I.
Wu
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HY
Department of Biological Chemistry, Johns Hopkins University, School of Medicine, Baltimore, MD 21205.
Liu
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LF
D001483:Base Sequence; D004269:DNA, Bacterial / Q000737:chemistry* / Q000235:genetics; D004278:DNA, Superhelical / Q000737:chemistry* / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010957:Plasmids; D014176:Protein Biosynthesis; D012097:Repressor Proteins / Q000737:chemistry* / Q000378:metabolism; D014158:Transcription, Genetic
D004269:DNA, Bacterial; D004278:DNA, Superhelical; D012097:Repressor Proteins