Site-specific transition of cytosine to uracil via reversible DNA photoligation

Photo-reactive oligodeoxynucleotide-embedded nanovesicles (PROsomes) with switchable stability for efficient cellular uptake and gene knockdown

A photo-responsive nanovesicle is fabricated by polyion complex (PIC) formation between poly(ethylene glycol) (PEG)-block-polypeptides and photo-reactive oligodeoxynucleotides (PROs)/anti-sense oligonucleotides (ASOs). The ultraviolet (UV) light triggers reversible crosslinking between PROs and ASOs in the vesicular membrane, providing the nanovesicle with switchable stability under physiological conditions. The resulting nanovesicle allows efficient cellular internalization, leading to significant UV-triggered gene knockdown in cultured cells.

Changing blue fluorescent protein to green fluorescent protein using chemical RNA editing as a novel strategy in genetic restoration

Using the transition from cytosine of BFP (blue fluorescent protein) gene to uridine of GFP (green fluorescent protein) gene at position 199 as a model, we successfully controlled photochemical RNA editing to effect site-directed deamination of cytidine (C) to uridine (U). Oligodeoxynucleotides (ODNs) containing 5'-carboxyvinyl-2'-deoxyuridine ((CV) U) were used for reversible photoligation, and single-stranded 100-nt BFP DNA and in vitro-transcribed full-length BFP mRNA were the targets. Photo-cross-linking with the responsive ODNs was performed using UV (366 nm) irradiation, which was followed by heat treatment, and the cross-linked nucleotide was cleaved through photosplitting (UV, 312 nm). The products were analyzed using restriction fragment length polymorphism (RFLP) and fluorescence measurements. Western blotting and fluorescence-analysis results revealed that in vitro-translated proteins were synthesized from mRNAs after site-directed RNA editing. We detected substantial amounts of the target-base-substituted fragment using RFLP and observed highly reproducible spectra of the transition-GFP signal using fluorescence spectroscopy, which indicated protein stability. ODNc restored approximately 10% of the C-to-U transition. Thus, we successfully used non-enzymatic site-directed deamination for genetic restoration in vitro. In the near future, in vivo studies that include cultured cells and model animals will be conducted to treat genetic disorders.

Oligonucleotide-templated reactions for sensing nucleic acids

Oligonucleotide-templated reactions are useful for applying nucleic acid sensing. Various chemistries for oligonucleotide-templated reaction have been reported so far. Major scientific interests are focused on the development of signal amplification systems and signal generation systems. We introduce the recent advances of oligonucleotide-templated reaction in consideration of the above two points.

Site-specific photochemical RNA editing

Photo-induced artificial RNA editing was demonstrated using photo-reactive oligonucleotides containing 3-cyanovinylcarbazole nucleoside. This non-enzymatic and sequence-specific methodology will make a major contribution to the elucidation of RNA functions including non-coding RNAs and to the development of drugs based on sequence-specific RNA editing.

Highly selective detection of 5-methylcytosine using photochemical ligation

We report the nonenzymatic detection of 5-methylcytosine by using template-directed photoligation through 5-cyanovinyl-2'-deoxyuridine ((C)U) with high selectivity and present a new methylation detection method using a photoligation-based DNA chip assay.

Highly selective and sensitive template-directed photoligation of DNA via 5-carbamoylvinyl-2'-deoxycytidine

We describe a highly efficient template-directed photoligation of oligodeoxynucleotides (ODNs) through 5-carbamoylvinyl-2'-deoxycytidine ((CV)C). When an ODN containing (CV)C at the 5' end was photoirradiated with an ODN containing a pyrimidine base at the 3' end in the presence of template DNA, efficient photoligation was observed without any byproduct formation. Single nucleotide differences can be successfully distinguished by using photoligation-based DNA chip assay. [structure: see text]

Highly sequence specific RNA terminal labeling by DNA photoligation

We report the nonenzymatic terminal labeling of oligoribonucleotide (ORN) by using template-directed photoligation through 5-carboxyvinyl-2'-deoxyuridine ((CV)U) with high selectivity.