Abstract: A method of detecting a target sequence is provided, the method comprising: hybridizing an oligonucleotide probe with a nucleic acid present in a test sample, wherein the oligonucleotide probe has a hybridization sequence with respect to a target sequence of the nucleic acid and has at least one covalent bonding group that is crosslinkable with a target base in the target sequence by light irradiation, thereby forming an authentic hybridization product; irradiating light to the test sample after the hybridizing, wherein the covalent bonding group and the target sequence are crosslinked, thereby forming the authentic cross-liked hybridization product having a crosslinked structure; and denaturating the test sample by applying a denaturating condition in which the authentic crosslinked hybridization product is able to be maintained and a non-specific hybridization product is able to be dissociated and separating the oligonucleotide probe derived from the non-specific hybridization product.

Abstract: An agent for inhibiting the action of a target RNA based on RNA interference and ASO with a passenger strand and a guide strand for a target RNA, wherein both ends of double-stranded RNA formed pairing of the passenger strand and the guide strand are blunt ends, and one or two or more selected from the group consisting of the units represented by formula (1) and formula (2) below at the following positions (a) and (b): (a) 5? end side and 3? end side of the passenger strand, (b) 3? end side of the guide strand (in which X represents an oxygen atom or sulfur atom), (in which X represents an oxygen atom or sulfur atom).