title: Cationic metal-specific structures adopted by the poly(dG) region and the direct repeats in the chicken adult beta A globin gene promoter.
abstract: Naturally occurring contiguous deoxyguanine residues and their surrounding sequences in the chicken adult beta A globin gene promoter were analyzed for their inherent potential to adopt non-B DNA structures in supercoiled plasmid DNA. In particular, cationic effects on structure were studied by treating the supercoiled plasmid DNA harboring the chicken adult beta A globin 5' flanking sequence with an unpaired DNA base-specific probe, chloroacetaldehyde in the presence of either Mg++, Cu++, Zn++, Ca++ or Co++ ions. The chloroacetaldehyde-reactive bases were mapped at a single base resolution by a chemical cleavage method that specifically cleaves DNA at the chloroacetaldehyde modified sites. These experiments revealed that while Mg++ and Ca++ ions induce a dG.dG.dC triple helix structure at the contiguous dG residues, Zn++, Cu++ and Co++ ions induce yet another structure at the direct repeats immediately 5' of the dG residues. When Mg++ and Zn++ ions are both present, Zn++ inhibits the dG.dG.dC triplex at the contiguous dG residues and induces a particular non-B DNA structure at the adjacent direct repeats. The specific induction of non-B DNA structures by metal ions at the two adjacent sequences within the promoter region may be of biological significance.
authors.affiliation: La Jolla Cancer Research Foundation, CA 92037.
authors.forename: Y
authors.initials: Y
authors.lastname: Kohwi
mesh_terms: D000818:Animals; D002413:Cations, Divalent; D002645:Chickens; D005914:Globins / Q000235:genetics*; D008274:Magnesium; D009690:Nucleic Acid Conformation / Q000187:drug effects; D009710:Nucleotide Mapping; D011068:Poly G / Q000235:genetics*; D011089:Polydeoxyribonucleotides / Q000235:genetics; D011131:Polyribonucleotides / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000187:drug effects; D012091:Repetitive Sequences, Nucleic Acid / Q000187:drug effects; D015032:Zinc
chemical_list: D002413:Cations, Divalent; D011089:Polydeoxyribonucleotides; D011131:Polyribonucleotides; D011068:Poly G; C016681:poly(dG).poly(dC); C026628:poly(dG); D005914:Globins; D008274:Magnesium; D015032:Zinc