UV-LASER adjuvant-surfactant-facilitated delivery of mobile dsRNA to tomato plant vasculature and evidence of biological activity by gene knockdown in the potato psyllid.

Background: Double-stranded RNA (dsRNA) biopesticides are of interest for the abatement of insect vectors of pathogenic bacteria such as 'Candidatus Liberibacter', which infects both its psyllid and plant hosts. Silencing of genes essential for psyllids, or for Liberibacter, is anticipated to lead to mortality or impeded bacterial multiplication. Foliar delivery is preferred for biopesticide application; however, the cuticle impedes dsRNA penetration into the vasculature.

Characteristics of environmental RNAi in potato psyllid, (Sulc) (Hemiptera: Psylloidea: Triozidae).

RNA interference (RNAi) has potential to become a major tool for integrated management of insect pests of agricultural crops based on sequence-specificity and low doses of rapidly biodegradable dsRNA. Deploying 'environmental RNAi' for control of insect vectors of plant pathogens is of increasing interest for combatting emerging plant diseases. Hemipteran insect vectors, including psyllids, are vascular feeders, making their development difficult to control specifically by targeting with pesticidal chemistries.

Comparison of l-Carnitine and l-Carnitine HCL salt for targeted lung treatment of pulmonary hypertension (PH) as inhalation aerosols: Design, comprehensive characterization, in vitro 2D/3D cell cultures, and in vivo MCT-Rat model of PH.

Disrupted l-Carnitine (L-Car) homeostasis has been implicated in the development of pulmonary hypertension (PH). L-Car has been administered orally and intravenously causing systemic side effects. To the authors' knowledge, there are no reports using L-Car or L-Car HCl as an inhaled aerosol through the respiratory route in a targeted manner either from dry powder inhaler (DPI) or liquid delivery system.

The 3'-end region of the human PDGFR-β core promoter nuclease hypersensitive element forms a mixture of two unique end-insertion G-quadruplexes.

Background: While the most stable G-quadruplex formed in the human PDGFR-β promoter nuclease hypersensitive element (NHE) is the 5'-mid G-quadruplex, the 3'-end sequence that contains a 3'-GGA run forms a less stable G-quadruplex. Recently, the 3'-end G-quadruplex was found to be a transcriptional repressor and can be selectively targeted by a small molecule for PDGFR-β downregulation.

Method: We use 1D and 2D high-field NMR, in combination with Dimethylsulfate Footprinting, Circular Dichroism Spectroscopy, and Electrophoretic Mobility Shift Assay.

A New G-Quadruplex with Hairpin Loop Immediately Upstream of the Human BCL2 P1 Promoter Modulates Transcription.

The abnormal overexpression of the BCL2 gene is associated with many human tumors. We found a new 28-mer G-quadruplex-forming sequence, P1G4, immediately upstream of the human BCL2 gene P1 promoter. The P1G4 is shown to be a transcription repressor using a promoter-driven luciferase assay; its inhibitory effect can be markedly enhanced by the G-quadruplex-interactive compound TMPyP4.

The major G-quadruplex formed in the human BCL-2 proximal promoter adopts a parallel structure with a 13-nt loop in K+ solution.

The human BCL-2 gene contains a 39-bp GC-rich region upstream of the P1 promoter that has been shown to be critically involved in the regulation of BCL-2 gene expression. Inhibition of BCL-2 expression can decrease cellular proliferation and enhance the efficacy of chemotherapy. Here we report the major G-quadruplex formed in the Pu39 G-rich strand in this BCL-2 promoter region.

Solution structure of the major G-quadruplex formed in the human VEGF promoter in K+: insights into loop interactions of the parallel G-quadruplexes.

Unlabelled: Vascular endothelial growth factor (VEGF) proximal promoter region contains a poly G/C-rich element that is essential for basal and inducible VEGF expression. The guanine-rich strand on this tract has been shown to form the DNA G-quadruplex structure, whose stabilization by small molecules can suppress VEGF expression. We report here the nuclear magnetic resonance structure of the major intramolecular G-quadruplex formed in this region in K(+) solution using the 22mer VEGF promoter sequence with G-to-T mutations of two loop residues.

Solution structure of a 2:1 quindoline-c-MYC G-quadruplex: insights into G-quadruplex-interactive small molecule drug design.

Unimolecular parallel-stranded G-quadruplex structures are found to be prevalent in gene promoters. The nuclease hypersensitivity element III(1) (NHE III(1)) of the c-MYC promoter can form transcriptionally active and silenced forms, and the formation of DNA G-quadruplex structures has been shown to be critical for c-MYC transcriptional silencing. The solution structure of a 2:1 quindoline-G-quadruplex complex has been solved and shows unexpected features, including the drug-induced reorientation of the flanking sequences to form a new binding pocket.

DNA sequence selectivity of human topoisomerase I-mediated DNA cleavage induced by camptothecin.

In probing the mechanism of inhibition of hypoxia inducible factor (HIF-1) by campothecins, we investigated the ability of human topoisomerase I to bind and cleave HIF-1 response element (HRE), which contains the known camptothecin-mediated topoisomerase I cleavage site 5'-TG. We observed that the selection of 5'-TG by human topoisomerase I and topotecan depends to a large extent on the specific flanking sequences, and that the presence of a G at the -2 position (where cleavage occurs between -1 and +1) prevents the HRE site from being a preferred site for such cleavage. Furthermore, the presence of -2 T/A can induce the cleavage at a less preferred TC or TA site.

Polymorphism of human telomeric quadruplex structures.

Human telomeric DNA consists of tandem repeats of the sequence d(TTAGGG). Compounds that can stabilize the intramolecular DNA G-quadruplexes formed in the human telomeric sequence have been shown to inhibit the activity of telomerase and telomere maintenance, thus the telomeric DNA G-quadruplex has been considered as an attractive target for cancer therapeutic intervention. Knowledge of intramolecular human telomeric G-quadruplex structure(s) formed under physiological conditions is important for structure-based rational drug design and thus has been the subject of intense investigation.

Structure of the Hybrid-2 type intramolecular human telomeric G-quadruplex in K+ solution: insights into structure polymorphism of the human telomeric sequence.

Formation of the G-quadruplex in the human telomeric sequence can inhibit the activity of telomerase, thus the intramolecular telomeric G-quadruplexes have been considered as an attractive anticancer target. Information of intramolecular telomeric G-quadruplex structures formed under physiological conditions is important for structure-based drug design. Here, we report the first structure of the major intramolecular G-quadruplex formed in a native, non-modified human telomeric sequence in K(+) solution.

Human topoisomerase I C-terminal domain fragment containing the active site tyrosine is a molten globule: implication for the formation of competent productive complex.

Human topoisomerase I (topo I) is an essential cellular enzyme that relaxes DNA supercoiling. The 6.3 kDa C-terminal domain of topo I contains the active site tyrosine (Tyr723) but lacks enzymatic activity by itself.

An intramolecular G-quadruplex structure with mixed parallel/antiparallel G-strands formed in the human BCL-2 promoter region in solution.

We report the first G-quadruplex structure formed in the promoter region of the human bcl-2. Bcl-2 is a potent oncoprotein that functions as an inhibitor of cell apoptosis and has been found to be aberrantly overexpressed in a wide range of human tumors. A highly GC-rich region upstream of the P1 promoter plays an important role in the regulation of the transcriptional activity of the bcl-2 oncogene.