| abstract |
There is disclosed a compound having a double chain which is composed of an RNA (+chain) and a complementary DNA (-chain), wherein a portion of the DNA (-chain) has been replaced by an RNA or a derivative thereof, and wherein, when the compound is subjected to the action of an enzyme having a ribonuclease H activity, it is possible to preferentially cleave the RNA (+chain) in a position corresponding to the unsubstituted portion of the DNA (-chain). The compound can thus be used for the preferential cleavage of a phosphodiester bond in a specific position of RNA. Accordingly, the invention provides a useful means for preparing, for instance, a deletion mutant. There is also disclosed a mixed oligomer which comprises an oligomer of RNA or a derivative thereof and a DNA oligomer, wherein the RNA oligomer or a derivative thereof is conjugated to the DNA oligomer via a phosphate diester linkage between the 5'-hydroxyl group and the 3'-hydroxyl group in the ribose or deoxyribose moiety. There is further disclosed a nucleoside derivative of a given general formula for use as a starting material. |