Intramolecular triple helices have been obtained by folding back twice oligonucleotides formed by decamers bound by non-nucleotide linkers: dA10-linker-dA10-linker-dT10 and dA10-linker-dT10-linker-dA10. We have thus prepared two triple helices with forced third strand orientation, respectively antiparallel (apA*A-T) and parallel (pA*A-T) with respect to the adenosine strand of the Watson-Crick ...

Several oligodeoxynucleotides (ODNs) were designed in order to interact with the purine rich element of the IRE (Interferon Responsive Element) of the 6-16 gene by triplex formation. An ODN of 21 bases, the sequence being identical to that of the purine strand of the IRE (48% G), but in reverse orientation, was able to interact with the IRE (KD: 20 nM). The binding was Mg2+ dependent. The two p...

We developed a novel large-diameter graft "Triplex(®)" that uses a non-biodegradable material as a coating material. This time, in order to demonstrate the physical properties of Triplex(®) grafts, we conducted physical tests in accordance with the international guidelines, using the collagen coated vascular grafts (Hemashield, Boston Scientific, Natick, Massachusetts, USA) as the controls. The...

A triplex-forming oligopyrimidine has been attached at its 5'-end to a photoreactive psoralen derivative and used to target a sequence which forms part of the coding region of the human aromatase gene. The 20 base pair sequence is not a perfect triplex target since it contains three pyrimidine interruptions within the purine-rich strand. Despite this, we have detected triplex-directed photoaddu...

Klebsiella pneumoniae, Corynebacterium kutscheri, and Streptococcus pneumoniae are important pathogens that cause respiratory infections in laboratory rodents. In this study, we used species-specific triplex PCR analysis to directly detect three common bacterial pathogens associated with respiratory diseases. Specific targets were amplified with conventional PCR using the tyrB gene from K. pneu...

Triplex-forming oligonucleotides (TFOs) are synthetic DNA code-reading molecules that have been demonstrated to function to some extent in chromatin within cell nuclei. Here we have investigated the impact of DNA nuclear environment on the efficiency of TFO binding. For this study we have used locked nucleic acid-containing TFOs (TFO/LNAs) and we report the development of a rapid PCR-based meth...

Although autosomal dominant polycystic kidney disease is transmitted in an autosomal dominant fashion, there is evidence that the pathophysiology of cystogenesis involves a second hit somatic mutation superimposed upon the inherited germline mutation within the renal tubule cells. The polypurine.polypyrimidine (Pu.Py) tract of PKD1 intron 21 may play a role in promoting somatic mutations. To be...

Competition between triplex formation with double-stranded DNA and oligonucleotide self-association was investigated in 23mer GA and GT oligonucleotides containing d(GA)5 or d(GT)5 repeats. Whereas triplex formation with GT oligonucleotides was diminished when temperature increased from 4 to 37 degrees C, triplex formation with GA oligonucleotides was enhanced when temperature increased within ...

Expansion of (GAA)n repeats in the first intron of the Frataxin gene is associated with reduced mRNA and protein levels and the development of Friedreich's ataxia. (GAA)n expansions form non-canonical structures, including intramolecular triplex (H-DNA), and R-loops and are associated with epigenetic modifications. With the aim of interfering with higher order H-DNA (like) DNA structures within...

Since the first description of the canonical B-form DNA double helix, it has been suggested that alternative DNA, DNA-RNA, and RNA structures exist and act as functional genomic elements. Indeed, over the past few years it has become clear that, in addition to serving as a repository for genetic information, genomic DNA elicits biological responses by adopting conformations that differ from the...