Submillimolar levels of calcium regulates DNA structure at the dinucleotide repeat (TG/AC)n.
basic_science · Level V
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- Record sourced from PubMed, PMID 9600903.
- Also identified by PMC identifier 27571.
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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.
Medical subject headings
- Brain
- Calcium
- DNA
- Nucleic Acid Conformation