Patent ID: 8115055

Claim:
An isolated nucleic acid fragment comprising the deoxyribonucleotide sequence set forth in SEQ ID NO:15 wherein (i) nucleotides 83 to 103 of SEQ ID NO:15 are replaced by a first variable nucleotide subsequence ranging in size from 19 to 24 nucleotides depending upon a target sequence whose expression is to be reduced, (ii) nucleotides 172 to 192 of SEQ ID NO:15 are replaced by a second variable nucleotide subsequence ranging in size from 19 to 24 nucleotides, said second variable nucleotide subsequence being capable of hybridizing to the first variable subsequence of the precursor miRNA, and (iii) the precursor miRNA produced by said isolated nucleic acid fragment has the same stem structure as the precursor miRNA produced by endogenous SEQ ID NO:15.