Abstract: A single-stranded antisense oligonucleotide, or a pharmaceutically acceptable salt thereof, capable of modulating expression and/or function of RPS25 gene, wherein nucleotides of the single-stranded antisense oligonucleotide are bonded to each other via a phosphate group and/or a modified phosphate group, the single-stranded antisense oligonucleotide includes a gap region, a 3? wing region bonded to a 3? end of the gap region, and a 5? wing region bonded to a 5? end of the gap region, the gap region is a deoxyribose-based nucleic acid optionally including a nucleic acid having a modified sugar moiety, each of the 3? wing region and the 5? wing region is a modified nucleotide, the single-stranded antisense oligonucleotide has a base length of 12- to 30-mer, and a base sequence of the antisense oligonucleotide is: a base sequence with a sequence identity of 90% to 100% to a base sequence complementary to at least one target region of the same base length as the antisense oligonucleotide present in the base sequ

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: 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: Provided is an oligonucleic acid analog which contains, as at least one structural unit thereof, a modified nucleic acid monomer compound which is a ring-open nucleoside having a cleaved carbon-carbon bond between the 2? and 3? positions and a substituent hydroxymethyl group at the 4? position. When used as siRNA, the oligonucleic acid analog exhibits superior biological stability and target gene expression inhibiting activity. The oligonucleic acid analog can be used in antisense methods, ribozyme methods, and decoy methods, etc., can be used as a nucleic acid aptamer, and can also be used as a nucleic acid probe or molecular beacon, etc., or in genetic diagnostics, etc.

Abstract: Provided is an oligonucleic acid analog which contains, as at least one structural unit thereof, a modified nucleic acid monomer compound which is a ring-open nucleoside having a cleaved carbon-carbon bond between the 2? and 3? positions and a substituent hydroxymethyl group at the 4? position. When used as siRNA, the oligonucleic acid analog exhibits superior biological stability and target gene expression inhibiting activity. The oligonucleic acid analog can be used in antisense methods, ribozyme methods, and decoy methods, etc., can be used as a nucleic acid aptamer, and can also be used as a nucleic acid probe or molecular beacon, etc., or in genetic diagnostics, etc.

Abstract: There is a demand for a convenient production method of an NC type purine nucleoside. The present invention relates to a method of producing a purine nucleoside represented the formula (I?) or a salt thereof, which comprising reacting a pyrimidine nucleoside represented by the formula (I) or a salt thereof with a purine nucleobase represented by the formula B?H in the presence of a Lewis acid.

Abstract: Provided is a new production method for the synthesis of an NC type nucleoside efficiently and conveniently in a high yield without unnecessary protecting group conversion steps. It relates to a step of producing a compound represented by the formula (II): or a salt thereof, by inverting a compound represented by the formula (I): and a method of producing a compound represented by the formula (III): or a salt thereof (wherein each symbol is as defined in the specification), which includes the step.

Abstract: There is a demand for a convenient production method of an NC type purine nucleoside. The present invention relates to a method of producing a purine nucleoside represented the formula (I?) or a salt thereof, which comprising reacting a pyrimidine nucleoside represented by the formula (I) or a salt thereof with a purine nucleobase represented by the formula B?H in the presence of a Lewis acid.