Distinctive aspects of ligand binding to G4 DNA structure flanked by the double helix.

Except for telomeres, G4 DNA structures in the human genome can be formed only within the context of double-stranded DNA. DNA duplexes flanking the G4 structure may potentially affect the G4 architecture and the binding of G4-specific ligands. Here, we examine the interaction of TMPyP4, NMM, and PDS ligands with three structures formed by the same DNA fragment containing the (GGGT) sequence: the G4 in duplex (dsG4), G4 in single-stranded DNA (ssG4) and perfect duplex DNA (ds).

Quenching of G4-DNA intrinsic fluorescence by ligands.

G-quadruplex (G4) structures formed by the guanine-rich DNA regions exhibit several distinctive optical properties, including UV absorption and circular dichroism spectra. Some G4 DNA possess intrinsic UV fluorescence whose origin is not completely clear to date. In this work, we study the effect of TMPyP4 and Methylene Blue on the intrinsic fluorescence of the dimeric G4 DNA structure formed by two d(GT) sequences.

Taq-Polymerase Stop Assay to Determine Target Selectivity of G4 Ligands in Native Promoter Sequences of , , and Oncogenes.

Computational and high-throughput experimental methods predict thousands of potential quadruplex sequences (PQSs) in the human genome. Often these PQSs contain more than four G-runs, which introduce additional uncertainty into the conformational polymorphism of the G4 DNA. G4-specific ligands, which are currently being actively developed as potential anticancer agents or tools for studying G4 structures in genomes, may preferentially bind to specific G4 structures over the others that can be potentially formed in the extended G-rich genomic region.

Differential Impact of Random GC Tetrad Binding and Chromatin Events on Transcriptional Inhibition by Olivomycin A.

Olivomycin A (OA), an antibiotic of the aureolic acid family, interferes with gene transcription upon forming complexes with GC-rich regions in the DNA minor groove. We demonstrate that the mechanism of transcriptional deregulation is not limited to OA interaction with GC-containing binding sites for transcription factors. Using electrophoretic mobility shift assays and DNAse I footprinting of cytomegalovirus (CMV) promoter fragments carrying OA-preferred GC tetrads (CMVwt), we showed OA binding specifically to GC islands.

Genome Assembly and Sex-Determining Region of Male and Female × .

The genus is presented by dioecious species, and it became a promising object to study the genetics of sex in plants. In this work, genomes of male and female × individuals were sequenced for the first time. To achieve high-quality genome assemblies, we used Oxford Nanopore Technologies and Illumina platforms.