Abstract: The invention provides a single-stranded oligonucleotide represented by the formula (I), wherein X and Y hybridize by a first nucleotide sequence portion and a second nucleotide sequence portion. X is composed of 7 to 100 nucleotides, contains at least one modified-nucleotide, and has a first nucleotide sequence capable of hybridizing with a second oligonucleotide. Y is composed of 4 to 100 nucleotides, enables hybridization with the above-mentioned first oligonucleotide, and has a second nucleotide sequence containing at least one ribonucleotide. At least one of the nucleotide sequences X, Xz and Y has an antisense sequence capable of hybridizing with a target RNA. At least one of L, Lx and Ly is a linking group that contains a non-nucleotide structure.

Abstract: Provided is a single-stranded oligonucleotide that is capable of controlling a target gene with high efficiency and can be easily produced. The single-stranded oligonucleotide is represented by the formula X-L-Y wherein X and Y hybridize by a first nucleotide sequence portion and a second nucleotide sequence portion. X is composed of 7 to 100 nucleotides, contains at least one modified nucleotide, and has a first nucleotide sequence that is capable of hybridizing with a second oligonucleotide and contains at least four contiguous nucleotides recognized by RNase H. Y is composed of 4 to 100 nucleotides, and has a second nucleotide sequence that is capable of hybridizing with a second oligonucleotide and contains at least one ribonucleotide. At least one of nucleotide sequence X and nucleotide sequence Y has an antisense sequence capable of hybridizing with a target RNA. L is a group derived from a third oligonucleotide that is degraded under physiological conditions.

Abstract: The invention provides a single-stranded oligonucleotide represented by the formula [Xz — Lx]m — X — Y — [Ly — Yz]n, wherein X is represented by Xa-Xb, Xa is coupled with Y, and Xb and Y hybridize. Xa is composed of 1 to 40 nucleotides and contains at least one modified-nucleotide. Xb is composed of 4 to 40 nucleotides and contains at least one modified-nucleotide. Y is composed of 4 to 40 nucleotides and contains at least one ribonucleotide. Xz and Yz are composed of 5 to 40 nucleotides and contain at least one modified-nucleotide. Nucleotide sequences X, Xz and Yz have an antisense sequence capable of hybridizing with a target RNA. Lx and Ly are composed of 0 to 20 nucleotides.

Abstract: The present invention provides a compound or a pharmaceutically acceptable salt thereof containing a modified oligonucleotide with a length of 8 to 80 consecutive nucleosides, in which the modified oligonucleotide has a nucleobase sequence containing at least 8 consecutive nucleobases contained in a nucleobase sequence of any one of SEQ ID NOs: 3 to 73. With the compound or a pharmaceutically acceptable salt thereof, it is possible to treat a disease or a condition against which inhibition of CALM2 gene expression by controlling of the CALM2 gene expression is effective (particularly, congenital long QT syndrome).

Abstract: The invention provides an antisense oligonucleotide capable of controlling ATN1 gene expression and treating dentatorubral-pallidoluysian atrophy. An inventive compound comprises a modified oligonucleotide consisting of 8 to 80 linked nucleosides and having a nucleobase sequence including at least 8 contiguous nucleobases that are complementary to a transcript of ATN1, or a pharmacologically acceptable salt thereof.

Abstract: The invention provides a single-stranded oligonucleotide represented by the formula (I), wherein X and Y hybridize by a first nucleotide sequence portion and a second nucleotide sequence portion. X is composed of 7 to 100 nucleotides, contains at least one modified-nucleotide, and has a first nucleotide sequence capable of hybridizing with a second oligonucleotide. Y is composed of 4 to 100 nucleotides, enables hybridization with the above-mentioned first oligonucleotide, and has a second nucleotide sequence containing at least one ribonucleotide. At least one of the nucleotide sequences X, Xz and Y has an antisense sequence capable of hybridizing with a target RNA. At least one of L, Lx and Ly is a linking group that contains a non-nucleotide structure.

Abstract: The invention provides a single-stranded oligonucleotide represented by the formula [Xz-Lx]m-X-Y-[Ly-Yz]n, wherein X is represented by Xa-Xb, Xa is coupled with Y, and Xb and Y hybridize. Xa is composed of 1 to 40 nucleotides and contains at least one modified-nucleotide. Xb is composed of 4 to 40 nucleotides and contains at least one modified-nucleotide. Y is composed of 4 to 40 nucleotides and contains at least one ribonucleotide. Xz and Yz are composed of 5 to 40 nucleotides and contain at least one modified-nucleotide. Nucleotide sequences X, Xz and Yz have an antisense sequence capable of hybridizing with a target RNA. Lx and Ly are composed of 0 to 20 nucleotides.

Abstract: Provided is a single-stranded oligonucleotide that is capable of controlling a target gene with high efficiency and can be easily produced. The single-stranded oligonucleotide is represented by the formula X-L-Y wherein X and Y hybridize by a first nucleotide sequence portion and a second nucleotide sequence portion. X is composed of 7 to 100 nucleotides, contains at least one modified nucleotide, and has a first nucleotide sequence that is capable of hybridizing with a second oligonucleotide and contains at least four contiguous nucleotides recognized by RNase H. Y is composed of 4 to 100 nucleotides, and has a second nucleotide sequence that is capable of hybridizing with a second oligonucleotide and contains at least one ribonucleotide. At least one of nucleotide sequence X and nucleotide sequence Y has an antisense sequence capable of hybridizing with a target RNA. L is a group derived from a third oligonucleotide that is degraded under physiological conditions.

Abstract: Provided is an artificial nucleoside or artificial nucleotide capable of composing an artificial oligonucleotide having superior nuclease resistance. The artificial nucleoside or artificial nucleotide is a compound represented by formula (I) or a salt thereof (wherein, Bx represents a pyrimidine base or purine base, R1, R2, R3 and R4 represent hydrogen atoms, C1-6 alkyl groups or the like, Y represents NR5R6 (wherein, R5 and R6, independently of each other, represent a hydrogen atom, C1-6 alkyl group or the like, or R5 and R6, together with a nitrogen atom bound thereto, form a 3- to 11-membered nitrogen-containing non-aromatic heterocyclic group) or an optionally substituted C2-9 aromatic heterocyclic group, Z1 and Z2 represent hydrogen atoms, hydroxyl group-protecting groups, phosphorous-containing groups or the like, and n represents an integer of 1 to 3).

Abstract: This is to provide a composition for delivering a nucleic acid and a nucleic acid-containing composition which ensure stability of a nucleic acid drug, have a high intracellular introduction rate, can efficiently express the function of a nucleic acid drug, and have low cytotoxicity. Disclosed is a composition for delivering a nucleic acid and a nucleic acid-containing composition each comprises a block copolymer in which a polyethylene glycol segment and a hydrophobic polyester segment are linked, and a peptide having 4 to 30 residues containing at least one selected from the group consisting of arginine and lysine.

Abstract: The invention provides a single-stranded oligonucleotide represented by the formula (I), wherein X and Y hybridize by a first nucleotide sequence portion and a second nucleotide sequence portion. X is composed of 7 to 100 nucleotides, contains at least one modified-nucleotide, and has a first nucleotide sequence capable of hybridizing with a second oligonucleotide. Y is composed of 4 to 100 nucleotides, enables hybridization with the above-mentioned first oligonucleotide, and has a second nucleotide sequence containing at least one ribonucleotide. At least one of the nucleotide sequences X, Xz and Y has an antisense sequence capable of hybridizing with a target RNA. At least one of L, Lx and Ly is a linking group that contains a non-nucleotide structure.

Abstract: Provided is an artificial nucleoside or artificial nucleotide capable of composing an artificial oligonucleotide having superior nuclease resistance. The artificial nucleoside or artificial nucleotide is a compound represented by formula (I) or a salt thereof (wherein, Bx represents a pyrimidine base or purine base, R1, R2, R3 and R4 represent hydrogen atoms, C1-6 alkyl groups or the like, Y represents NR5R6 (wherein, R5 and R6, independently of each other, represent a hydrogen atom, C1-6 alkyl group or the like, or R5 and R6, together with a nitrogen atom bound thereto, form a 3- to 11-membered nitrogen-containing non-aromatic heterocyclic group) or an optionally substituted C2-9 aromatic heterocyclic group, Z1 and Z2 represent hydrogen atoms, hydroxyl group-protecting groups, phosphorous-containing groups or the like, and n represents an integer of 1 to 3).

Abstract: This is to provide a composition for delivering a nucleic acid and a nucleic acid-containing composition which ensure stability of a nucleic acid drug, have a high intracellular introduction rate, can efficiently express the function of a nucleic acid drug, and have low cytotoxicity. Disclosed is a composition for delivering a nucleic acid and a nucleic acid-containing composition each comprises a block copolymer in which a polyethylene glycol segment and a hydrophobic polyester segment are linked, and a peptide having 4 to 30 residues containing at least one selected from the group consisting of arginine and lysine.

Abstract: The invention provides an antisense oligonucleotide reduced in toxicity. The antisense oligonucleotide has a central region, a 5?-side region and a 3?-side region, wherein the central region has a nucleotide (2?-3? bridged nucleotide) in which the 2?-position and the 3?-position of a sugar moiety are bridged and/or a non-bridged nucleotide (3?-position-modified non-bridged nucleotide) having a substituent at the 3?-position.

Abstract: The invention provides a single-stranded oligonucleotide represented by the formula [Xz-Lx]m-X-Y-[Ly-Yz]n, wherein X is represented by Xa-Xb, Xa is coupled with Y, and Xb and Y hybridize. Xa is composed of 1 to 40 nucleotides and contains at least one modified-nucleotide. Xb is composed of 4 to 40 nucleotides and contains at least one modified-nucleotide. Y is composed of 4 to 40 nucleotides and contains at least one ribonucleotide. Xz and Yz are composed of 5 to 40 nucleotides and contain at least one modified-nucleotide. Nucleotide sequences X, Xz and Yz have an antisense sequence capable of hybridizing with a target RNA. Lx and Ly are composed of 0 to 20 nucleotides.

Abstract: Provided is a single-stranded oligonucleotide that is capable of controlling a target gene with high efficiency and can be easily produced. The single-stranded oligonucleotide is represented by the formula X-L-Y wherein X and Y hybridize by a first nucleotide sequence portion and a second nucleotide sequence portion. X is composed of 7 to 100 nucleotides, contains at least one modified nucleotide, and has a first nucleotide sequence that is capable of hybridizing with a second oligonucleotide and contains at least four contiguous nucleotides recognized by RNase H. Y is composed of 4 to 100 nucleotides, and has a second nucleotide sequence that is capable of hybridizing with a second oligonucleotide and contains at least one ribonucleotide. At least one of nucleotide sequence X and nucleotide sequence Y has an antisense sequence capable of hybridizing with a target RNA. L is a group derived from a third oligonucleotide that is degraded under physiological conditions.

Abstract: The invention provides a process for producing a ?-dihydrofuran derivative represented by formula (1) or a ?-tetrahydrofuran derivative represented by formula (4), characterized in that the process includes causing a dialkyl dicarbonate, a diaralkyl dicarbonate, or a halide to act on a diol compound represented by formula (2) or (3). The invention also provides a process for producing 4?-ethynyl-2?,3?-didehydro-3?-deoxythymidine or an analog thereof, the process including glycosylation and deprotection.

Abstract: The invention provides a process for producing a ?-glycoside compound represented by formula (3), characterized in that the process includes causing to react a cyclic alkene compound represented by formula (1) or (2) with a nucleophile in the presence of a transition metal catalyst.

Abstract: An acylating agent and a hydrolase are caused to act on a hydroxypyranone represented by formula (I) in a water-containing organic solvent, to thereby produce an acyloxypyranone compound represented by formula (II) (wherein R1 represents an acyl group). Then, an acetylene organic metal compound represented by formula (III) (wherein R2 represents a hydrogen atom or a tri-substituted silyl group, and M represents an alkali metal atom, aluminum, or a magnesium monohalide) and a coordinating additive are caused to act on the acyloxypyranone compound represented by formula (II), to thereby produce an alkyne compound represented by formula (IV). The alkyne compound represented by formula (IV) is hydrolyzed with acid, to thereby produce a dihydrofuran compound represented by formula (V).

Abstract: The present invention herein provides a process for production of a bicyclo[2.2.2]octylamine derivative which may be used as an intermediate for preparation of medical and pharmaceutical products. The process is quite efficient and can produce the derivative in a large-scale while using mild reaction conditions. The process for producing a bicyclo[2.2.