title: Rapid "footprinting" on supercoiled DNA.
abstract: A DNase protection technique is described and applied to the interaction of three lac control proteins with supercoiled lac DNA. The technique uses end-labeled oligonucleotide primers to probe specific DNA regions as an alternative to protocols requiring restriction endonuclease cleavage or blotting. Thus DNA may be probed with high resolution in its native state. It is demonstrated that the introduction of supercoiling into DNA accelerates the rate of lac ps promoter binding by RNA polymerase but does not alter the positions at which polymerase, c-AMP-binding protein, or lac repressor bind to lac DNA.
mesh_terms: D001665:Binding Sites; D002874:Chromosome Mapping; D004278:DNA, Superhelical / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D003851:Deoxyribonucleases; D004926:Escherichia coli / Q000235:genetics; D007700:Kinetics; D007763:Lac Operon; D010957:Plasmids; D011401:Promoter Regions, Genetic; D011953:Receptors, Cyclic AMP / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D004278:DNA, Superhelical; D011953:Receptors, Cyclic AMP; D012097:Repressor Proteins; D012321:DNA-Directed RNA Polymerases; D003851:Deoxyribonucleases