PROBLEM TO BE SOLVED: To provide a linear double-stranded DNA for expression of mutant RNA, of which introduction into a cell without its circularization enables expression of mutant RNA in the cell.SOLUTION: Prepared linear double-stranded DNA for expressing mutant RNA is one of the following DNAa, DNAb and DNAc, where DNAa comprises Sequence 1', a terminator sequence, a promoter sequence and Sequence 2, in this order; DNAb comprises Sequence 1, a terminator sequence, a promoter sequence and Sequence 2', in this order; and DNAc comprises Sequence 1', a terminator sequence, a promoter sequence and Sequence 2', in this order; wherein Sequence 1 corresponds to the downstream region of a DNA sequence for RNA expression, Sequence 1' is a sequence having a mutation at the 5' terminal region of Sequence 1, Sequence 2 corresponds to the upstream region of the DNA sequence for RNA expression, and Sequence 2' is a sequence having a mutation at the 3' terminal region of Sequence 2.
