Abstract: The present invention provides a process for preparing an isotope-containing phosphate compound easily. The process for preparing an isotope-containing phosphate compound according to the present invention includes the step of oxidizing a trivalent phosphorus compound with an oxidizing agent containing an isotope to synthesize a pentavalent phosphate compound to which the isotope has been introduced. The present invention preferably is applied to the synthesis of nucleic acids such as DNA and RNA, for example. The isotope preferably is a stable isotope. The oxidizing agent preferably is H218O, 3H-1,2-benzodithiol 3-one 1,1-dioxide having 34S, or a diisopropylethylamine-borane complex having 10B, for example.

Abstract: Provided is a novel nucleic acid molecule that can be produced easily and efficiently and can inhibit the expression of a gene. The nucleic acid molecule is a single-stranded nucleic acid molecule including an expression inhibitory sequence that inhibits expression of a target gene. The single-stranded nucleic acid molecule includes: a region (X); a linker region (Lx); and a region (Xc). The linker region (Lx) is linked between the regions (Xc) and (Xc). The region (Xc) is complementary to the region (X). At least one of the regions (X) and (Xc) includes the expression inhibitory sequence. The linker region (Lx) has a non-nucleotide structure including at least one of a pyrrolidine skeleton and a piperidine skeleton. According to this single-stranded nucleic acid molecule, it is possible to inhibit the expression of the target gene.

Abstract: Provided is a novel nucleic acid molecule that can be produced easily and efficiently and can inhibit the expression of a gene. The nucleic acid molecule is a single-stranded nucleic acid molecule including an expression inhibitory sequence that inhibits expression of a target gene. The single-stranded nucleic acid molecule includes: a region (X); a linker region (Lx); and a region (Xc). The linker region (Lx) is linked between the regions (Xc) and (Xc). The region (Xc) is complementary to the region (X). At least one of the regions (X) and (Xc) includes the expression inhibitory sequence. The linker region (Lx) has a non-nucleotide structure including at least one of a pyrrolidine skeleton and a piperidine skeleton. According to this single-stranded nucleic acid molecule, it is possible to inhibit the expression of the target gene.

Abstract: Provided is a novel nucleic acid molecule that can inhibit the expression of a gene and can be produces easily and efficiently. The nucleic acid molecule is a single-stranded nucleic acid molecule including an expression inhibitory sequence that inhibits expression of a target gene. The single-stranded nucleic acid molecule includes, in sequence from the 5? side to the 3? side: a 5? side region (Xc); an inner region (Z); and a 3? side region (Yc). The inner region (Z) is composed of an inner 5? side region (X) and an inner 3? side region (Y) that are linked to each other. The 5? side region (Xc) is complementary to the inner 5? side region (X). The 3? side region (Yc) is complementary to the inner 3? side region (Y). At least one of the inner region (Z), the 5? side region (Xc), and the 3? side region (Yc) includes the expression inhibitory sequence. According to this single-stranded nucleic acid molecule, it is possible to inhibit the expression of the target gene.