I-motif Structures Formed in the Human C-MYC Promoter Are Highly Dynamic--insights into Sequence Redundancy and I-motif Stability

Overview

Journal PLoS One

Specialties General Medicine
Science

Date 2010 Jul 27

PMID 20657837

Citations 35

Authors

Jixun Dai

Emmanuel Hatzakis

Laurence H Hurley

Danzhou Yang

Affiliations

Soon will be listed here.

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 I-motif. 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.

Citing Articles

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