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 UNA could bind calcium and can compete with calmodulin for calcium.
|Number of pages||6|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - 26 May 1998|