I-motif structures formed in the human c-MYC promoter are highly dynamic-insights into sequence redundancy and I-motif stability

Jixun Dai, Emmanuel Hatzakis, Laurence H. Hurley, Danzhou Yang

Research output: Contribution to journalArticle

38 Scopus citations

Abstract

The GC-rich nuclease hypersensitivity element III1 (NHE III1) of the c-MYC promoter largely controls the transcriptional activity of the c-MYC oncogene. The C-rich strand in this region can form I-motif DNA secondary structures. We determined the folding pattern of the major I-motif formed in the NHE III1, which can be formed at near-neutral pH. While we find that the I-motif formed in the four 3′ consecutive runs of cytosines appears to be the most favored, our results demonstrate that the C-rich strand of the c-MYC NHE III1 exhibits a high degree of dynamic equilibration. Using a trisubstituted oligomer of this region, we determined the formation of two equilibrating loop isomers, one of which contains a flipped-out cytosine. Our results indicate that the intercalative cytosine+-cytosine base pairs are not always necessary for an intramolecular Imotif. The dynamic character of the c-MYC I-motif is intrinsic to the NHE III1 sequence and appears to provide stability to the c-MYC I-motif.

Original languageEnglish (US)
Article numbere11647
JournalPloS one
Volume5
Issue number7
DOIs
StatePublished - Jul 19 2010

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)
  • General

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