Abstract: The present invention provides a novel bridged artificial nucleic acid and an oligomer containing the same as a monomer. The present invention provides specifically a compound represented by general formula (I) (wherein each symbol is the same as defined in the specification) or salts thereof; as well as an oligonucleotide compound represented by general formula (I?) (wherein each symbol is the same as defined in the specification) or salts thereof.

Abstract: A method of reducing the level of a transcription product in a cell comprising contacting with the cell a composition comprising a double-stranded nucleic acid complex comprising a first nucleic acid strand annealed to a second nucleic acid strand, wherein: (i) the first nucleic acid strand hybridizes to the transcription product and comprises (a) a region consisting of at least 4 consecutive nucleotides that are recognized by RNase H when the strand is hybridized to the transcription product, (b) one or more nucleotide analogs located on 5? terminal side of the region, (c) one or more nucleotide analogs located on 3? terminal side of the region and (d) a total number of nucleotides and nucleotide analogs ranging from 8 to 35 nucleotides and (ii) the second nucleic acid strand comprises (a) nucleotides and optionally nucleotide analogs and (b) at least 4 consecutive RNA nucleotides.

Abstract: The purpose of the present invention is to provide an antisense oligonucleotide that targets an ARL4C molecule and exerts an antitumor effect in vivo, and a nucleic acid drug using the antisense oligonucleotide. An antisense oligonucleotide that has a base sequence consisting of at least 10 consecutive bases contained in the base sequence represented by SEQ ID NO: 1. This antisense oligonucleotide targets an ARL4C molecule and thus can inhibit the expression of ARL4C in a tumor cell in vitro and suppress the migration and proliferation thereof. When systemically administered, moreover, the antisense oligonucleotide can exert an excellent antitumor effect in vivo too.

Abstract: Disclosed is an oligonucleotide or a pharmacologically acceptable salt thereof, wherein the oligonucleotide comprises at least one defined nucleoside structure, can bind to a human nSR100 gene and has human nSR100 expression inhibiting activity. The oligonucleotide has a length of 12 to 20 mer, and is complementary to a defined target region. Further, disclosed is an nSR100 gene expression inhibitor and a cancer therapeutic agent containing the oligonucleotide or the pharmacologically acceptable salt thereof. The cancer therapeutic agent is used for treatment of small cell lung cancer, prostate cancer, or breast cancer.

Abstract: A method of reducing the level of a transcription product in a cell comprising contacting with the cell a composition comprising a double-stranded nucleic acid complex comprising a first nucleic acid strand annealed to a second nucleic acid strand, wherein: (i) the first nucleic acid strand hybridizes to the transcription product and comprises (a) a region consisting of at least 4 consecutive nucleotides that are recognized by RNase H when the strand is hybridized to the transcription product, (b) one or more nucleotide analogs located on 5? terminal side of the region, (c) one or more nucleotide analogs located on 3? terminal side of the region and (d) a total number of nucleotides and nucleotide analogs ranging from 8 to 35 nucleotides and (ii) the second nucleic acid strand comprises (a) nucleotides and optionally nucleotide analogs and (b) at least 4 consecutive RNA nucleotides.

Abstract: Provided is an oligonucleotide conjugate comprising an oligonucleotide and two or more linearly connected asialoglycoprotein receptor-binding molecules attached to the oligonucleotide, wherein the oligonucleotide comprises a locked nucleoside analog having a bridging structure between the 4? and 2? positions, is complementary to a human PCSK9 gene, and has inhibitory activity on the expression of the human PCSK9 gene. The oligonucleotide conjugate of the present invention can be used in the field of pharmaceutical products, in particular, the field of the development and production of therapeutic agents for diseases associated with a high LDL cholesterol level.

Abstract: The present invention provides an antisense oligonucleotide for inhibiting biosynthesis of chondroitin sulfate. The antisense oligonucleotide comprises at least one modified nucleotide, wherein the antisense oligonucleotide suppresses expression of one or both of the chondroitin sulfate N-acetylgalactosaminyltransferase-1 (CSGalNAcT1) gene and the chondroitin sulfate N-acetylgalactosaminyltransferase-2 (CSGalNAcT2) gene.

Abstract: A method for preparing a compound represented by general formula I: or a salt thereof includes a step of reacting a compound represented by formula II: with a reducing agent to cleave an oxazolidine ring fused to a cycle A?. The reducing agent includes at least one of phosphines, metal hydrides, or transition metal catalysts in the presence of hydrogen gas.

Abstract: The objective of the present invention is to provide nucleic acid therapeutics which exhibits more excellent effect and which shows a substantivity for a prolonged period to suppress an expression of ?-synuclein. The oligonucleotide or a pharmacologically acceptable salt thereof according to the present invention is characterized in comprising at least one 2?-O,4?-C-ethylene nucleoside, wherein the oligonucleotide can hybridize with ?-synuclein gene, has an activity to suppress an expression of the ?-synuclein gene, and is complementary to the ?-synuclein gene, 5? end of the oligonucleotide is a nucleotide complementary to the specific nucleotide, the oligonucleotide is complementary to at least a part of SEQ ID NO: 1, and the oligonucleotide has a length of 13 or more and 15 or less nucleotides.

Abstract: The present invention aims to provide an antisense oligonucleic acid with reduced hepatotoxicity. The antisense oligonucleic acid according to the present invention is characterized in that it has a base length of not less than 7 nt and not more than 30 nt, wherein nucleic acid residues of not less than 1 nt and not more than 5 nt respectively from the both terminals are 2?,4?-bridged nucleic acids, 2?,4?-non-bridged nucleic acid residue(s) is(are) present between the above-mentioned both terminals, and one or more bases in the nucleic acid residue(s) of the above-mentioned 2?,4?-non-bridged nucleic acid residue(s) is/are modified.

Abstract: The present invention aims to provide a nucleic acid compound that hardly forms non-Watson-Crick base pairs, and an oligonucleotide containing the nucleic acid compound and showing reduced non-specific binding with nucleic acids other than the target nucleic acid. The nucleic acid compound according to the present invention is characterized in that the 2-position carbonyl group of the pyrimidine base is functionally converted (X1 and X2 are each independently S or Se), and that the 2?-position and the 4?-position are bridged in a particular structure. The oligonucleotide according to the present invention is characterized in that at least one of thymidine and uridine is the nucleic acid compound.

Abstract: A method of reducing the level of a transcription product in a cell comprising contacting with the cell a composition comprising a double-stranded nucleic acid complex comprising a first nucleic acid strand annealed to a second nucleic acid strand, wherein: (i) the first nucleic acid strand hybridizes to the transcription product and comprises (a) a region consisting of at least 4 consecutive nucleotides that are recognized by RNase H when the strand is hybridized to the transcription product, (b) one or more nucleotide analogs located on 5? terminal side of the region, (c) one or more nucleotide analogs located on 3? terminal side of the region and (d) a total number of nucleotides and nucleotide analogs ranging from 8 to 35 nucleotides and (ii) the second nucleic acid strand comprises (a) nucleotides and optionally nucleotide analogs and (b) at least 4 consecutive RNA nucleotides.

Abstract: A compound represented by formula I or II below or a salt thereof: wherein B1 represents a purin-9-yl group or a 2-oxo-1,2-dihydropyrimidin-1-yl group that has any one or more substituents selected from the group consisting of a hydroxyl group, a hydroxyl group protected by a protecting group in nucleic acid synthesis, a C1 to C6 linear alkyl group, a C1 to C6 linear alkoxy group, a mercapto group, a mercapto group protected by a protecting group in nucleic acid synthesis, a C1 to C6 linear alkylthio group, an amino group, a C1 to C6 linear alkylamino group, an amino group protected by a protecting group in nucleic acid synthesis, and a halogen atom.

Abstract: A method of reducing the level of a transcription product in a cell comprising contacting with the cell a composition comprising a double-stranded nucleic acid complex comprising a first nucleic acid strand annealed to a second nucleic acid strand, wherein: (i) the first nucleic acid strand hybridizes to the transcription product and comprises (a) a region consisting of at least 4 consecutive nucleotides that are recognized by RNase H when the strand is hybridized to the transcription product, (b) one or more nucleotide analogs located on 5? terminal side of the region, (c) one or more nucleotide analogs located on 3? terminal side of the region and (d) a total number of nucleotides and nucleotide analogs ranging from 8 to 35 nucleotides and (ii) the second nucleic acid strand comprises (a) nucleotides and optionally nucleotide analogs and (b) at least 4 consecutive RNA nucleotides.

Abstract: A method of reducing the level of a transcription product in a cell comprising contacting with the cell a composition comprising a double-stranded nucleic acid complex comprising a first nucleic acid strand annealed to a second nucleic acid strand, wherein: (i) the first nucleic acid strand hybridizes to the transcription product and comprises (a) a region consisting of at least 4 consecutive nucleotides that are recognized by RNase H when the strand is hybridized to the transcription product, (b) one or more nucleotide analogs located on 5? terminal side of the region, (c) one or more nucleotide analogs located on 3? terminal side of the region and (d) a total number of nucleotides and nucleotide analogs ranging from 8 to 35 nucleotides and (ii) the second nucleic acid strand comprises (a) nucleotides and optionally nucleotide analogs and (b) at least 4 consecutive RNA nucleotides.

Abstract: Disclosed are double-stranded antisense nucleic acid complexes that can efficiently alter the processing of RNA in a cell via an antisense effect, and methods for using the same. One method comprises contacting with the cell a double-stranded nucleic acid complex comprising: a first nucleic acid strand annealed to a second nucleic acid strand, wherein: the first nucleic acid strand comprises (i) nucleotides independently selected from natural DNA nucleotides, modified DNA nucleotides, and nucleotide analogs, (ii) no regions that have 4 or more consecutive natural DNA nucleotides, (iii) the total number of natural DNA nucleotides, modified DNA nucleotides, and nucleotide analogs in the first nucleic acid strand is from 8 to 100, and (iv) the first nucleic acid strand is capable of hybridizing to RNA inside of the cell; and the second nucleic acid strand comprises nucleotides independently selected from natural RNA nucleotides, modified RNA nucleotides, and nucleotide analogs.

Abstract: The present invention can provide a nucleic acid medicine which has a higher effect and a more prolonged effect of inhibiting the expression of ?-synudein can be provided. Disclosed is the oligonucleotide or a pharmacologically acceptable salt thereof, the oligonucleotide containing at least one nucleoside structure represented by Formula (I): (where each of Base and A are defined substituent or structure), can bind to an ?-synudein gene, has activity for inhibiting expression of the ?-synudein gene, and is complementary to the ?-synudein gene, and the oligonucleotide has a length of twelve to twenty bases.

Abstract: A method of reducing the level of a transcription product in a cell comprising contacting with the cell a composition comprising a double-stranded nucleic acid complex comprising a first nucleic acid strand annealed to a second nucleic acid strand, wherein: (i) the first nucleic acid strand hybridizes to the transcription product and comprises (a) a region consisting of at least 4 consecutive nucleotides that are recognized by RNase H when the strand is hybridized to the transcription product, (b) one or more nucleotide analogs located on 5? terminal side of the region, (c) one or more nucleotide analogs located on 3? terminal side of the region and (d) a total number of nucleotides and nucleotide analogs ranging from 8 to 35 nucleotides and (ii) the second nucleic acid strand comprises (a) nucleotides and optionally nucleotide analogs and (b) at least 4 consecutive RNA nucleotides.

Abstract: The present invention provides a method for producing guanidine crosslinked artificial nucleic acid (abbreviated hereinafter as GuNA), and an intermediate compound for the production thereof. Specifically, the present invention provides a method for producing a compound represented by general formula I: (in the formula, R1, R2, R3, R4, R5, R6, m and ring A are as defined in the specification) or a salt thereof wherein a reducing agent is reacted with a compound represented by general formula II: (in the formula, R1, R2, R3, R4, R5, R6, m, and ring A? are as defined in the specification).

Abstract: A method of reducing the level of a transcription product in a cell comprising contacting with the cell a composition comprising a double-stranded nucleic acid complex comprising a first nucleic acid strand annealed to a second nucleic acid strand, wherein: (i) the first nucleic acid strand hybridizes to the transcription product and comprises (a) a region consisting of at least 4 consecutive nucleotides that are recognized by RNase H when the strand is hybridized to the transcription product, (b) one or more nucleotide analogs located on 5? terminal side of the region, (c) one or more nucleotide analogs located on 3? terminal side of the region and (d) a total number of nucleotides and nucleotide analogs ranging from 8 to 35 nucleotides and (ii) the second nucleic acid strand comprises (a) nucleotides and optionally nucleotide analogs and (b) at least 4 consecutive RNA nucleotides.