Method and medicament for inhibiting the expression of a given gene
View Patent ↗The present invention relates to the specific inhibition of expression of a target gene in mammals using a short double stranded RNA. The dsRNA is less than 49 nucleotides in length and has a nucleotide sequence which is complementary to at least a part of the target gene. The dsRNAs of the present invention are useful for treating diseases, for example, cancer, viral diseases or neurodegenerative diseases.
1. A method for inhibiting expression of a target gene in a mammalian cell in vitro, comprising:
a) introducing into said mammalian cell in vitro an isolated double stranded RNA (dsRNA) consisting of two separate oligoribonucleotide single strands that are chemically linked by a disulfide bridge, wherein one strand of said dsRNA is complementary to an RNA transcript of at least part of said target gene and the other strand of the dsRNA is complementary to the first strand, and wherein the dsRNA is 21 base pairs in length; and
b) maintaining the cell produced in step a) for a time sufficient to obtain degradation of an RNA transcript of said target gene, wherein said dsRNA, when introduced into the presence of said RNA transcript, reduces an amount of said RNA transcript via dsRNA-mediated interference, thereby inhibiting the expression of said target gene in said cell in vitro.
2. The method of claim 1 , wherein at least one of said strands comprises at least one chemically modified nucleotide.
3. The method of claim 2 , wherein said chemically modified nucleotide is a 2′-modified nucleotide.
4. The method of claim 3 , wherein said 2′-modified nucleotide is a 2′-methyl substituted nucleotide.
5. The method of claim 3 , wherein said 2′-modified nucleotide is a 2′-amino substituted nucleotide.
6. The method of claim 2 , wherein said chemically modified nucleotide is a locked nucleotide.
7. The method of claim 1 , wherein the target gene is a mammalian gene or a viral gene.
8. The method of claim 1 , wherein the target gene is selected from the group consisting of an oncogene, a cytokine gene, an Id protein gene, a developmental gene, a PKR gene and a prion gene.
9. The method of claim 1 , wherein the two separate single strands hybridize to each other to form the dsRNA.
10. The method of claim 1 , wherein each of the single strands is complementary to the other of the single strands, and neither is autocomplementary.
11. The method of claim 1 , wherein inhibiting the expression of said target gene further comprises inhibiting expression at a concentration of the dsRNA that is lower by one order of magnitude than a concentration required for a corresponding single-stranded oligoribonucleotide to inhibit expression.