Guanine-rich DNA strands can fold in vitro into noncanonical DNA structures called G-quadruplexes. These structures may be very stable under physiological conditions. Evidence suggests that Gquadruplex structures may act as ‘knots’ within genomic DNA, and it has been hypothesized that proteins may have evolved to remove these structures. The first indication of how G-quadruplex structures could...

G-quadruplexes are nucleic acid secondary structures formed from guanine-rich sequences, and comprise a planar arrangement of four guanines that are stabilized by Hoogsteen hydrogen bonding and cations. These structures have been widely implicated in the control of gene expression for a number of eukaryotic systems. Stabilization of G-quadruplex has been shown to modulate the level of gene expr...

Understanding the nature of the interaction between small molecules and G-quadruplex DNA is crucial for the development of novel anticancer drugs. In this paper, we present the first data on time-resolved fluorescence anisotropy study on the interaction between a water-soluble cationic porphyrin H(2)TMPyP4 and four distinct G-quadruplex DNAs, that is, AG(3)(T(2)AG(3))(3), thrombin-binding aptam...

At present, wt1, a Wilms' tumor suppressor gene, is recognized as a critical regulator of tumorigenesis and a potential therapeutic target. WT1 shows the ability to regulate the transcription of bcl-2 by binding to a GC-rich region in the promoter, which can then fold into a special DNA secondary structure called the G-quadruplex. This function merits the exploration of the effect of a G-quadru...

Gold nanoparticles have been used as a probe to detect low (<10 ppb) concentrations of quadruplex DNA. These nanoparticles display a tendency to form aggregates in the presence of certain quadruplex forms, as observed via enhanced plasmon resonance light scattering (PRLS) signals. These nanoparticles showed differing degrees of interactions with different types of quadruplex and mixed sequences...

Molecular recognition of DNA quadruplex structures is envisioned to be a strategy for regulating gene expression at the transcriptional level and for in situ analysis of telomere structure and function. The recognition of DNA quadruplexes by peptide nucleic acid (PNA) oligomers is presented here, with a focus on comparing complementary, heteroduplex-forming and homologous, heteroquadruplex-form...

A quadruplex loop-mediated isothermal amplification (LAMP) method was developed to detect four Vibrio species, including Vibrio ichthyoenteri, Vibrio parahaemolyticus, Vibrio scophthalmi, and Vibrio vulnificus, simultaneously. Four sets of species-specific primers were designed with different restriction sites contained in the inner primers. The quadruplex LAMP method could distinguish four Vib...

The development of small molecules is essential to modulate the cellular functions of biological targets in living system. Target Guided Synthesis (TGS) approaches have been used for the identification of potent small molecules for biological targets. We herein demonstrate an innovative example of TGS using DNA nano-templates that promote Huisgen cycloaddition from an array of azide and alkyne ...

G-quadruplexes, four-stranded structures formed by Guanine-rich nucleic acids, are implicated in many physiological and pathological processes. G-quadruplex-forming sequences are abundant in genomic DNA, and G-quadruplexes have recently been shown to exist in the genome of mammalian cells. However, how G-quadruplexes are formed in the genomes remains largely unclear. Here, we show that G-quadru...

Human telomeric DNA composed of (TTAGGG/CCCTAA)n repeats may form a classical Watson-Crick double helix. Each individual strand is also prone to quadruplex formation: the G-rich strand may adopt a G-quadruplex conformation involving G-quartets whereas the C-rich strand may fold into an i-motif based on intercalated C*C+ base pairs. Using an equimolar mixture of the telomeric oligonucleotides d[...