Human genomic DNA is widely interspersed with i-motif structures.

DNA i-motif structures are formed in the nuclei of human cells and are believed to provide critical genomic regulation. While the existence, abundance, and distribution of i-motif structures in human cells has been demonstrated and studied by immunofluorescent staining, and more recently NMR and CUT&Tag, the abundance and distribution of such structures in human genomic DNA have remained unclear. Here we utilise high-affinity i-motif immunoprecipitation followed by sequencing to map i-motifs in the purified genomic DNA of human MCF7, U2OS and HEK293T cells.

Protocol for the production and purification of an i-Motif-specific nanobody.

Intercalated motifs or i-Motifs (iMs) are nucleic acid structures formed by cytosine-rich sequences, which may regulate cellular processes and have broad applications in nanotechnology due to their pH-dependent nature. We have developed an iM-specific nanobody (iMbody) that can recognize iM DNA structures regardless of their sequences, making it a versatile research tool for studying iMs in various contexts. Here, we provide a protocol for the bacterial expression and His-tag purification of iMbody.

The retroelement Lx9 puts a brake on the immune response to virus infection.

The notion that mobile units of nucleic acid known as transposable elements can operate as genomic controlling elements was put forward over six decades ago. However, it was not until the advancement of genomic sequencing technologies that the abundance and repertoire of transposable elements were revealed, and they are now known to constitute up to two-thirds of mammalian genomes. The presence of DNA regulatory regions including promoters, enhancers and transcription-factor-binding sites within transposable elements has led to the hypothesis that transposable elements have been co-opted to regulate mammalian gene expression and cell phenotype.

Selection of Antibody Fragments Against Structured DNA by Phage Display.

In addition to the canonical B-form structure, DNA can adopt alternative conformations including Z DNA, triplex DNA, as well as G4 and i-Motif quadruplex structures. Such structures have been shown to form in cells in a dynamic manner. Monoclonal antibodies against such structures represent key tools to study the biological functions of these structures.

I-motif DNA structures are formed in the nuclei of human cells.

Human genome function is underpinned by the primary storage of genetic information in canonical B-form DNA, with a second layer of DNA structure providing regulatory control. I-motif structures are thought to form in cytosine-rich regions of the genome and to have regulatory functions; however, in vivo evidence for the existence of such structures has so far remained elusive. Here we report the generation and characterization of an antibody fragment (iMab) that recognizes i-motif structures with high selectivity and affinity, enabling the detection of i-motifs in the nuclei of human cells.

Structural basis of antigen recognition: crystal structure of duck egg lysozyme.

Duck egg lysozyme (DEL) is a widely used model antigen owing to its capacity to bind with differential affinity to anti-chicken egg lysozyme antibodies. However, no structures of DEL have so far been reported, and the situation had been complicated by the presence of multiple isoforms and conflicting reports of primary sequence. Here, the structures of two DEL isoforms from the eggs of the commonly used Pekin duck (Anas platyrhynchos) are reported.

Cancer-associated noncoding mutations affect RNA G-quadruplex-mediated regulation of gene expression.

Cancer is a multifactorial disease driven by a combination of genetic and environmental factors. Many cancer driver mutations have been characterised in protein-coding regions of the genome. However, mutations in noncoding regions associated with cancer have been less investigated.

Propranolol hydrochloride osmotic capsule with controlled onset of release.

Hard gelatin capsule was coated by a cellulose acetate as a semipermeable membrane with or without castor oil and filled with propranolol hydrochloride and sorbitol as an osmotic agent. After sealing the capsule with white bees wax plug, the onset of release and dissolution rate of the drug were studied. Water penetration into the capsule from the dissolution medium increases simultaneously the osmotic and hydrostatic pressures of its content.