Abstract: The present invention provides a nucleic acid conjugate in which a sugar chain ligand is bonded to an oligonucleotide via a linker, the sugar chain ligand having O-bonded mannose at its non-reducing end.

Abstract: An oligonucleotide having improved affinity for AGO2 is disclosed. The oligonucleotide has a nucleotide residue or a nucleoside residue represented by formula (I) wherein X1 is an oxygen atom or the like, R1 is formula (IIA), wherein R5A is halogen or the like, and R6A is a hydrogen atom or the like, or formula (IVA) wherein Y3A is a nitrogen atom or the like, and Y4A is CH or the like, or the like, R2 is a hydrogen atom, hydroxy, halogen, or optionally substituted lower alkoxy, and R3 is a hydrogen atom or the like at the 5? end thereof, and the nucleotide residue or the nucleoside residue binds to an adjacent nucleotide residue through the oxygen atom at position 3. A method for improving the knockdown activity of an oligonucleotide wherein the oligonucleotide has a knockdown activity against an mRNA encoding a protein involved in a disease.

Abstract: An oligonucleotide having a nucleotide residue or a nucleoside residue represented by formula (I) {wherein X1 is an oxygen atom or the like, R1 is formula (IIA) (wherein R5A is halogen or the like, and R6A is a hydrogen atom or the like), formula (IVA) (wherein Y3A is a nitrogen atom or the like, and Y4A is CH or the like), or the like, R2 is a hydrogen atom, hydroxy, halogen, or optionally substituted lower alkoxy, and R3 is a hydrogen atom or the like, or formula (VI) (wherein n2 is 1, 2 or 3)} at the 5? end thereof, wherein the nucleotide residue or the nucleoside residue binds to an adjacent nucleotide residue through the oxygen atom at position 3, is provided.

Abstract: The present invention provides a nucleic acid conjugate in which a sugar chain ligand is bonded to an oligonucleotide via a linker, the sugar chain ligand having O-bonded mannose at its non-reducing end.

Abstract: The present invention provides a nucleic acid conjugate comprising: a double-stranded nucleic acid consisting of a sense strand and an antisense strand and comprising a duplex region of at least 11 base pairs; and a ligand part, wherein an oligonucleotide with a strand length of 17 to 30 nucleotides in the antisense strand is complementary to a target ?2GPI mRNA sequence, and the 3? end or 5? end of the sense strand has a ligand part represented by following formula (I), formula (II), formula (III), formula (IV) or formula (V).

Abstract: An oligonucleotide having a nucleotide residue or a nucleoside residue represented by formula (I) {wherein X1 is an oxygen atom or the like, R1 is formula (IIA) (wherein R5A is halogen or the like, and R6A is a hydrogen atom or the like), formula (IVA) (wherein Y3A is a nitrogen atom or the like, and Y4A is CH or the like), or the like, R2 is a hydrogen atom, hydroxy, halogen, or optionally substituted lower alkoxy, and R3 is a hydrogen atom or the like, or formula (VI) (wherein n2 is 1, 2 or 3)} at the 5? end thereof, wherein the nucleotide residue or the nucleoside residue binds to an adjacent nucleotide residue through the oxygen atom at position 3, is provided.

Abstract: The present invention provides an oligonucleotide having improved affinity for AGO2, and the like. The oligonucleotide has a nucleotide residue or a nucleoside residue represented by formula (I) {wherein X1 is an oxygen atom or the like, R1 is formula (IIA) (wherein R5A is halogen or the like, and R6A is a hydrogen atom or the like) or formula (IVA) (wherein Y3A is a nitrogen atom or the like, and Y4A is CH or the like), or the like, R2 is a hydrogen atom, hydroxy, halogen, or optionally substituted lower alkoxy, and R3 is a hydrogen atom or the like} at the 5? end thereof, and the nucleotide residue or the nucleoside residue binds to an adjacent nucleotide residue through the oxygen atom at position 3.

Abstract: An oligonucleotide, which has a nucleotide residue or a nucleoside residue represented by formula (I) at the 5? end thereof, wherein the nucleotide residue or the nucleoside residue binds to an adjacent nucleotide residue via the oxygen atom at position 3, or the like; wherein X represents an oxygen atom or the like, R1 represents formula (II) wherein Y1 represents a nitrogen atom or the like, R5 represents halogen or the like, R6 and R7 may be the same or different, and each represents a hydrogen atom or the like, and R3 represents a hydrogen atom or the like.