Double-stranded antisense nucleic acids with exon skipping effect

Double-stranded antisense nucleic acid complexes via an antisense effect can change the processing of RNA in cells efficiently, and methods of using the same are disclosed. One method is the cell, A first nucleic acid strand annealed to a second nucleic acid strand, wherein: The first nucleic acid strand comprises a nucleotide selected independently (i) natural DNA nucleotides, modified DNA nucleotides, and nucleotide analogs, not including the region having the (ii) 4 or more contiguous naturally occurring DNA nucleotides, (iii) natural DNA nucleotides of the first nucleic acid strand, the total number of modified DNA nucleotides, and nucleotide analogs are 8 to 100, and (iv) a first nucleic acid strand can hybridize to RNA in a cell by and; more second nucleic acid strand comprises a naturally occurring RNA nucleotides, a nucleotide independently selected modified RNA nucleotides, and nucleotide analogs, Comprising contacting a double-stranded nucleic acid complex comprising a first nucleic acid strand annealed to the second nucleic acid strand. .The