Tagcyx Biotechnologies

Riken Corporation

Japan Science and Technology Agency

Agency for Science, Technology and Research

Japan Science and Technology Corporation

Ichiro Hirao

Shigeyuki Yokoyama

Michiko Hirao

Tsuneo Mitsui

Rie Yamashige

Kenichiro Matsunaga

Kensaku Sakamoto

Masahide Ishikawa

Tsuyoshi Fujihara

Shun-ichi Sekine

Ryuya Fukunaga

Daisuke Kiga

Kazunobu Futami

Shuang Liu

Iwao Nozawa

Yoko Harada

An object of the present invention is to provide a convenient and low-cost method for enhancing the stability of a DNA aptamer and/or its capacity to bind to a target molecule, and a DNA aptamer obtained by the method. The object is solved by substituting an internal hairpin structure (stem-loop structure) of the DNA aptamer with a structure called mini-hairpin structure and optionally increasing GC pairs in a stem portion of the DNA aptamer.

Method for stabilizing DNA aptamers

The purpose of the present invention is to provide an aptamer to a cancer cell, said aptamer being superior to conventional aptamers in binding ability, specificity, and/or stability. To solve this problem, provided is a DNA aptamer binding to a cancer cell, said DNA aptamer containing an artificial base(s).

DNA aptamer binding to cancer cell

The purpose of the present invention is to provide an aptamer for vWF, which is superior in a binding ability, a dissociation rate, and/or stability to the conventional nucleic acid aptamers. The present invention can solve the problem by a DNA aptamer which contains artificial nucleotides and binds to vWF.

DNA aptamer that binds to vWF

This invention is intended to enhance and improve the resistance of a single- or double-stranded nucleic acid fragment comprising a base sequence of a functional nucleic acid to degradation by nucleolytic enzymes in a simple and cost-effective manner. The single- or double-stranded nucleic acid fragment comprises, ligated to at least one end thereof, hairpin-shaped DNA comprising: (A) a nucleic acid region comprising 2 to 5 arbitrary nucleotides; (B) a nucleic acid region comprising a 'gna' or 'gnna' base sequence, wherein each 'n' represents &#x201c;g&#x201d;, &#x201c;t&#x201d;, &#x201c;a&#x201d;, or &#x201c;c&#x201d;, a base analogue, or a modified base; and (C) a nucleic acid region comprising a base sequence complementary to the nucleic acid region (A), sequentially from the 5' end toward the 3&#x2032; end.

Stabilization method of functional nucleic acid

An object of the present invention is to develop and provide a method for efficiently producing a nucleic acid aptamer, particularly, a DNA aptamer, having higher specificity and binding activity against a target substance than those of nucleic acid aptamers obtained by conventional methods. The present invention provides a transcribable or replicable nucleic acid aptamer comprising a natural nucleotide and a non-natural nucleotide having an artificial base-pairable artificial base. The present invention also provides a method for sequencing a non-natural nucleotide-containing single-stranded nucleic acid molecule selected from a single-stranded nucleic acid library.

Nucleic acid fragment binding to target protein

An object of the present invention is to develop and provide a method for efficiently and conveniently producing a nucleic acid aptamer, particularly, a DNA aptamer, having high specificity for and high binding activity against a target substance.

Method for preparing nucleic acid aptamer

It is an object of the present invention to provide quenching or fluorescent nucleic acid base analogs and applications thereof. The quencher of the present invention has a 2-nitropyrrole structure represented by Formula I: [Formula 1] (in Formula I, Rand Rare groups independently selected from the group consisting of:

Nucleic acid base analogs with quenching and fluorescent activities and applications thereof

The present invention provides a double-stranded nucleic acid in which at least one nucleic acid strand includes an unnatural base that forms a self-complementary base pair or an unnatural base that forms a base pair with any natural base with substantially the same thermal stability. The present invention also provides a method of hybridizing a first nucleic acid strand with a second nucleic acid strand, wherein the first nucleic acid strand includes an unnatural base that forms a self-complementary base pair or an unnatural base that forms a base pair with any natural base with substantially the same thermal stability, and a method of applying the nucleic acid to SNP detection, a DNA chip, DNA/RNA computing, or an in vitro translation system. The present invention provides a method of introducing an unnatural base into a nucleic acid strand and thereby controlling the thermodynamic stability in hybridization of the nucleic acid strand.

Artificial base pair capable of forming specific base pair

In the method for introducing a noncanonical amino acid residue into a desired position in a protein, the structure of tRNA is so modified as to have improved affinity for aminoacyl-tRNA synthetase or improved specificity to aminoacyl-tRNA synthetase. An unnatural base is contained at any position in tRNA, whereby the efficiency of aminoacylation of the tRNA with a noncanonical amino acid can be improved.

Modified tRNA containing unnatural base and use thereof

The present invention relates to novel unnatural fluorescent nucleic acid bases, that is, a purine base, a 1-deazapurine base, and a 1,7-deazapurine base each having a functional group which consists of two or more heterocyclic moieties linked together, at the 6-position thereof (the 6-position of purine ring). The present invention also relates to a compound containing the unnatural base, a derivative thereof, and a nucleic acid containing a nucleotide having the unnatural base. The present invention also relates to a method of preparing the nucleic acid. The unnatural base of the present invention has excellent fluorescence characteristics and also has excellent properties as a universal base.

Artificial fluorescent bases

The present invention relates to unnatural base pairs of Ds (a 7-(2 thienyl)-3H-imidazo[4,5-b]pyridine-3-yl group) and a Pa derivative (a 2-nitro-1H-pyrrole-1-yl group bearing a substituent having a &#x3c0;-electron system attached at position 4) that can be replicated with high selectivity/high efficiency, and methods for replicating nucleic acids containing the unnatural base pairs. The present invention also relates to methods for incorporating an unnatural base bearing a functional substituent attached thereto into DNA by a nucleic acid replication reaction. The present invention also relates to methods for replicating and selectively collecting a nucleic acid containing an unnatural base pair from a nucleic acid pool. The present invention also relates to methods for determining a sequence of natural bases in the proximity of an unnatural base in DNA for achieving highly efficient and highly selective replication of a nucleic acid containing the unnatural base.

DNA capable of being amplified by PCR with high selectivity and high efficiency

The present invention provides nucleic acids based on novel artificial base pairing, as well as a preparation method and uses thereof. In the nucleic acids of the present invention, a nucleotide having a substituted or unsubstituted 2-formyl-1H-pyrrol-1-yl group as a base forms a base pair with a nucleotide having a 6-substituted 9H-purin-9-yl group as a base. The inventive method for preparing a nucleic acid comprises effecting transcription, reverse transcription or replication by using, as a template, a nucleic acid incorporating a nucleotide having a substituted or unsubstituted 2-formyl-1H-pyrrol-1-yl group as a base, so that the nucleotide having a 6-substituted 9H-purin-9-yl group is incorporated at a site complementary to the nucleotide having a substituted or unsubstituted 2-formyl-1H-pyrrol-1-yl group.

Artificial base pairs and uses thereof

The present invention relates to a method for nucleic acid replication and novel artificial base pairs. The method of the present invention for nucleic acid replication is characterized in that a deoxyribonucleoside 5'-triphosphate, in which the hydroxyl group of phosphoric acid at the &#x3b3;-position is substituted with a group selected from the group consisting of an amino group, a methylamino group, a dimethylamino group, a mercapto group and a fluoro group, is used as a substrate during replication reaction. The novel artificial base pairs of the present invention are characterized in that 7-(2-thienyl)-imidazo[4,5-b]pyridine (Ds) or an analog thereof forms a base pair with pyrrole-2-carbaldehyde (Pa) or an analog thereof.

Growing community of inventors

Komae, Japan

Ichiro Hirao