%0 Journal Article
%T The Formation and Stabilization of a Novel G-Quadruplex in the 5¡ä-Flanking Region of the Relaxin Gene
%A Sen Lin
%A Huiping Gu
%A Ming Xu
%A Xiaojie Cui
%A Youyi Zhang
%A Wei Gao
%A Gu Yuan
%J PLOS ONE
%D 2012
%I Public Library of Science (PLoS)
%R 10.1371/journal.pone.0031201
%X It has been reported that binding of STAT3 protein to the 5¡ä-flanking region of the relaxin gene may result in downregulation of the relaxin expression. There is a Guanine(G)-rich segment located in about 3.8 Kb upstream of the relaxin gene and very close to the STAT3's binding site. In our study, NMR spectroscopy revealed the formation of G-quadruplex by this G-rich strand, and the result was confirmed by ESI mass spectrometry and CD spectroscopy. The theoretical structure of RLX G-quadruplex was constructed and refined by molecular modeling. When this relaxin G-quadruplex was stabilized by berberine(¦¤Tm = 10¡ãC), a natural alkaloid from a Chinese herb, the gene expression could be up-regulated in a dose-dependent manner which was proved by luciferase assay. This result is different from the general G-quadruplex function that inhibiting the telomere replication or down-regulating many oncogenes expression. Therefore, our study reported a novel G-quadruplex in the relaxin gene and complemented the regulation mechanism about gene expression by G-quadruplexes.
%U http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0031201