Learn More
A systematic study of the thermal and conformational properties of chemically modified G-quadruplexes of different molecularities is reported. The effect of backbone charge and atom size, thymine/uracyl substitution as well as the effect of modification at the ribose 2'-position was analyzed by UV spectroscopy. Additional calorimetric studies were performed(More)
We show that nucleic acid structures may be conveniently and inexpensively characterized by their UV thermal difference spectra. A thermal difference spectrum (TDS) is obtained for a nucleic acid by simply recording the ultraviolet absorbance spectra of the unfolded and folded states at temperatures above and below its melting temperature (T(m)). The(More)
The melting of tetramolecular DNA or RNA quadruplexes is kinetically irreversible. However, rather than being a hindrance, this kinetic inertia allows us to study association and dissociation processes independently. From a kinetic point of view, the association reaction is fourth order in monomer and the dissociation first order in quadruplex. The(More)
Parallel tetramolecular quadruplexes may be formed with short oligodeoxynucleotides bearing a block of three or more guanines. We analyze the properties of sequence variants of parallel quadruplexes in which each guanine of the central block was systematically substituted with a different base. Twelve types of substitutions were assessed in more than 100(More)
Short contiguous arrays of variant CTAGGG repeats in the human telomere are unstable in the male germline and somatic cells, suggesting formation of unusual structures by this repeat type. Here, we report on the structure of an intramolecular G-quadruplex formed by DNA sequences containing four human telomeric variant CTAGGG repeats in potassium solution.(More)
Most studies on the structure of DNA in telomeres have been dedicated to the double-stranded region or the guanosine-rich strand and consequently little is known about the factors that may bind to the telomere cytosine-rich (C-rich) strand. This led us to investigate whether proteins exist that can recognise C-rich sequences. We have isolated several(More)
Molecular beacons (MBs) are fluorescent nucleic acid probes with a hairpin-shaped structure in which the 5' and 3' ends are self-complementary. Due to a change in their emissive properties upon recognition with complementary sequences, MBs allow the diagnosis of single-stranded DNA or RNA with high mismatch discrimination, in vitro and in vivo. Whereas the(More)
Critical evidence for the biological relevance of G-quadruplexes (G4) has recently been obtained in seminal studies performed in a variety of organisms. Four-stranded G-quadruplex DNA structures are promising drug targets as these non-canonical structures appear to be involved in a number of key biological processes. Given the growing interest for G4,(More)
Interleukin-1 beta (Il-1 beta), a key cytokine in the acute phase response, elevates hepatic expression of both the heavy (H) and light (L) ferritin subunits without influencing the steady-state levels of either ferritin transcript. Transfection experiments with human hepatoma cells reveal that sequences within the 5' untranslated region (5'UTR) of(More)
RNA and DNA guanine-rich sequences can adopt unusual structures called Guanine quadruplexes (G4). A quadruplex-prone RNA sequence is present at the 5'-end of the 451-nt-long RNA component of telomerase, hTERC. As this quadruplex may interfere with P1 helix formation, a key structural element for this RNA, we are seeking molecules that would alter this RNA(More)