The present inventors identified RSIS, and succeeded in suppressing the expression of a target gene by linking RSIS between the region from the promoter to mRNA 5' end sequence of a target gene and a terminator sequence including the 3'UTR after the stop codon. Furthermore, the inventors demonstrated that the expression of two different genes could be suppressed at the same time in cells where a promoter was active, by using the promoter and terminator derived from different genes, and a portion of the mRNA of each gene.