title: Submillimolar levels of calcium regulates DNA structure at the dinucleotide repeat (TG/AC)n.
abstract: Submillimolar levels of calcium, similar to the physiological total (bound + free) intranuclear concentration (0.01-1 mM), induced a conformational change within d(TG/AC)n, one of the frequent dinucleotide repeats of the mammalian genome. This change is calcium-specific, because no other tested cation induced it and it was detected as a concentration-dependent transition from B- to a non-B-DNA conformation expanding from 3' end toward the 5' of the repeat. Genomic footprinting of various rat brain regions revealed the existence of similar non-B-DNA conformation within a d(TG/AC)28 repeat of the endogenous enkephalin gene only in enkephalin-expressing caudate nucleus and not in the nonexpressing thalamus. Binding assays demonstrated that DNA could bind calcium and can compete with calmodulin for calcium.
authors.affiliation: Molecular Control of Neurodifferentiation, Laboratory of Developmental Neurobiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: A
authors.initials: A
authors.lastname: Dobi
authors.forename: D
authors.initials: D
authors.lastname: v Agoston
mesh_terms: D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D004247:DNA / Q000737:chemistry / Q000187:drug effects / Q000502:physiology*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation / Q000187:drug effects*; D009711:Nucleotides / Q000737:chemistry / Q000502:physiology; D051381:Rats
chemical_list: D009711:Nucleotides; D004247:DNA; D002118:Calcium