H-DNA and Z-DNA in the mouse c-Ki-ras promoter

Dmitri G. Pestov, Andrey Dayn, Elena Yu Siyanova, Donna L. George, Sergei M. Mirkin

Research output: Contribution to journalArticlepeer-review

49 Scopus citations


The mouse c-Ki-ras protooncogene promoter contains a homopurine-homopyrimidine domain that exhibits S1 nuclease sensitivity in vitro. We have studied the structure of this DNA region in a supercoiled state using a number of chemical probes for non-B DNA conformations including diethyl pyrocarbonate, osmium tetroxide, chloroacetaldehyde, and dimethyl sulfate. The results demonstrate that two types of unusual DNA structures formed under different environmental conditions. A 27-bp homopurinehomopyrimidine mirror repeat adopts a triple-helical HDNA conformation under mildly acidic conditions. This H-DNA seems to account for the S1 hypersensitivity of the promoter in vitro, since the observed pattern of S1 hypersensitivity at a single base level fits well with the H-DNA formation. Under conditions of neutral pH we have detected Z-DNA created by a (CG)5-stretch, located adjacent to the homopurine-homopyrimidine mirror repeat. The ability of the promoter DNA segment to form non-B structures has implications for models of gene regulation.

Original languageEnglish (US)
Pages (from-to)6527-6532
Number of pages6
JournalNucleic acids research
Issue number23
StatePublished - Dec 11 1991
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Genetics


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