Details for Patent: 8,632,997

Title:	RNA sequence-specific mediators of RNA interference
Abstract:	The present invention relates to a Drosophila in vitro system which was used to demonstrate that dsRNA is processed to RNA segments 21-23 nucleotides (nt) in length. Furthermore, when these 21-23 nt fragments are purified and added back to Drosophila extracts, they mediate RNA interference in the absence of long dsRNA. Thus, these 21-23 nt fragments are the sequence-specific mediators of RNA degradation. A molecular signal, which may be their specific length, must be present in these 21-23 nt fragments to recruit cellular factors involved in RNAi. This present invention encompasses these 21-23 nt fragments and their use for specifically inactivating gene function. The use of these fragments (or chemically synthesized oligonucleotides of the same or similar nature) enables the targeting of specific mRNAs for degradation in mammalian cells, where the use of long dsRNAs to elicit RNAi is usually not practical, presumably because of the deleterious effects of the interferon response. This specific targeting of a particular gene function is useful in functional genomic and therapeutic applications.
Inventor(s):	Tuschl; Thomas (Goettingen, DE), Zamore; Phillip D. (Northborough, MA), Sharp; Phillip A. (Newton, MA), Bartel; David P. (Brookline, MA)
Assignee:	University of Massachusetts (Boston, MA) Whitehead Institute for Biomedical Research (Cambridge, MA) Massachusetts Institute of Technology (Cambridge, MA) Max-Planck-Gesellschaft zur Forderung der Wissenschaften E.V. (Munich, DE)
Filing Date:	Oct 04, 2010
Application Number:	12/897,749
Claims:	1. A method of producing a double-stranded RNA molecule of from 21 to 23 nucleotides in length that mediates RNA interference of an mRNA, comprising: (a) chemically synthesizing the double-stranded RNA molecule in the form of two separate complementary RNA strands which are not covalently linked and each RNA strand has a length of from 21 to 23 nucleotides, wherein the sequence of one strand has sufficient sequence correspondence to the mRNA to mediate RNA interference by directing cleavage of the mRNA within the region of sequence correspondence, and (b) combining the strands of (a) under conditions under which the double-stranded RNA molecule is produced, thereby producing the double-stranded RNA molecule of from 21 to 23 nucleotides that mediates RNA interference of the mRNA. 2. The method according to claim 1, wherein the RNA strands are recombinantly produced. 3. The method of claim 1, wherein the mRNA is a mammalian cellular mRNA. 4. The method of claim 1, wherein the RNA molecule comprises a terminal 3' hydroxyl group. 5. The method of claim 1, wherein one or more nucleotides of the double-stranded RNA molecule are a non-naturally occurring nucleotide. 6. The method of claim 1, wherein one or more nucleotides of the double-stranded RNA molecule are a deoxyribonucleotide. 7. The method of claim 1, wherein one or more nucleotides of the double-stranded RNA molecule are a non-standard nucleotide. 8. The method of claim 1, wherein the mRNA is a human mRNA. 9. The method of claim 1, wherein the mRNA is a viral mRNA. 10. The method of claim 1, wherein the double-stranded RNA molecule is perfectly complementary to the mRNA. 11. The method of claim 1, wherein the double-stranded RNA molecule is 21 nucleotides in length. 12. The method of claim 1, wherein the double-stranded RNA molecule is 22 nucleotides in length. 13. The method of claim 1, wherein the double-stranded RNA molecule is 23 nucleotides in length. 14. A method of producing a double-stranded RNA molecule of from 21 to 23 nucleotides in length that mediates RNA interference of an mRNA, comprising: chemically synthesizing the double-stranded RNA molecule such that the RNA is in the form of two separate complementary RNA strands which are not covalently linked and each RNA strand has a length of from 21 to 23 nucleotides, wherein the sequence of one strand has sufficient sequence correspondence to the mRNA to mediate RNA interference of the mRNA, and thereby producing the double-stranded RNA molecule of from 21 to 23 nucleotides that mediates RNA interference of the mRNA. 15. The method of claim 1, wherein the mRNA encodes a protein whose presence in a human is associated with a disease or undesirable condition. 16. The method of claim 1, wherein the double-stranded RNA molecule is effective to reduce expression of the mRNA. 17. The method of claim 1, further comprising testing the double-stranded RNA molecule to determine the level of RNA interference effected by the double-stranded RNA. 18. The method of claim 1, wherein each RNA strand of the double-stranded RNA molecule comprises a terminal 3' hydroxyl group. 19. The method of claim 1, wherein the double-stranded RNA molecule comprises one or more naturally occurring nucleotides. 20. The method of claim 1, wherein the double-stranded RNA molecule comprises one or more naturally occurring nucleotides and one or more non-naturally occurring nucleotides. 21. The method of claim 14, wherein the double-stranded RNA molecule comprises a terminal 3' hydroxyl group. 22. The method of claim 14, wherein each RNA strand of the double-stranded RNA molecule comprises a terminal 3' hydroxyl group. 23. The method of claim 14, wherein the double-stranded RNA molecule comprises one or more non-naturally occurring nucleotides. 24. The method of claim 14, wherein the double-stranded RNA molecule comprises one or more non-standard nucleotides. 25. The method of claim 14, wherein the double-stranded RNA molecule comprises one or more deoxyribonucleotides. 26. The method of claim 14, wherein the double-stranded RNA molecule comprises one or more naturally occurring nucleotides. 27. The method of claim 14, wherein the double-stranded RNA molecule comprises one or more naturally occurring nucleotides and one or more non-naturally occurring nucleotides. 28. The method of claim 14, wherein the mRNA is a mammalian cellular mRNA. 29. The method of claim 14, wherein the mRNA is a human mRNA. 30. The method of claim 14, wherein the mRNA encodes a protein whose presence in a human is associated with a disease or undesirable condition. 31. The method of claim 14, wherein the mRNA is a viral mRNA. 32. The method of claim 14, wherein the double-stranded RNA molecule is perfectly complementary to the mRNA. 33. The method of claim 14, wherein a strand of the double-stranded RNA molecule is 21 nucleotides in length. 34. The method of claim 14, wherein a strand of the double-stranded RNA molecule is 22 nucleotides in length. 35. The method of claim 14, wherein a strand of the double-stranded RNA molecule is 23 nucleotides in length. 36. A method of producing a double-stranded RNA molecule of 21 to 23 nucleotides in length that mediates RNA interference, comprising: synthesizing the double-stranded RNA molecule such that the RNA is in the form of two separate complementary RNA strands which are not covalently linked and each RNA strand has a length of from 21 to 23 nucleotides, wherein the sequence of one strand has sufficient sequence complementarity to a target mRNA to mediate RNA interference of the target mRNA, and wherein the double-stranded RNA molecule comprises one or more of: a non-naturally occurring nucleotide, a non-standard nucleotide, or a deoxyribonucleotide, thereby producing the double-stranded RNA molecule. 37. The method of claim 36, wherein a strand of the double-stranded RNA molecule is 21 nucleotides in length. 38. The method of claim 36, wherein a strand of the double-stranded RNA molecule is 22 nucleotides in length. 39. The method of claim 36, wherein a strand of the double-stranded RNA molecule is 23 nucleotides in length. 40. The method of claim 16, wherein the expression of the mRNA is determined using an in vitro RNA interference assay. 41. A method of producing a double-stranded RNA molecule of 21 to 23 nucleotides in length that mediates RNA interference, comprising: synthesizing the double-stranded RNA molecule such that the RNA is in the form of two separate complementary RNA strands which are not covalently linked and each RNA strand has a length of from 21 to 23 nucleotides, wherein one strand of the double-stranded RNA molecule is perfectly complementary to a target mRNA to mediate RNA interference of the target mRNA, thereby producing the double-stranded RNA molecule. 42. The method of claim 41, wherein a strand of the double-stranded RNA molecule is 21 nucleotides in length. 43. The method of claim 41, wherein a strand of the double-stranded RNA molecule is 22 nucleotides in length. 44. The method of claim 41, wherein a strand of the double-stranded RNA molecule is 23 nucleotides in length. 45. The method of claim 41, wherein the expression of the mRNA is determined using an in vitro RNA interference assay. 46. The method of claim 41, wherein both strands of the double-stranded RNA molecule are 21 nucleotides in length. 47. The method of claim 41, wherein both strands of the double-stranded RNA molecule are 22 nucleotides in length. 48. The method of claim 41, wherein both strands of the double-stranded RNA molecule are 23 nucleotides in length. 49. The method of claim 41, wherein the double-stranded RNA molecule comprises one or more non-naturally occurring nucleotides. 50. The method of claim 41, wherein the double-stranded RNA molecule comprises one or more non-standard nucleotides. 51. The method of claim 41, wherein the double-stranded RNA molecule comprises one or more deoxyribonucleotides. 52. The method of claim 41, wherein the mRNA is a cellular mRNA. 53. The method of claim 41, wherein the mRNA is an oncogene mRNA. 54. The method of claim 41, wherein the mRNA encodes a viral protein. 55. The method of claim 1, wherein the mRNA is a cellular mRNA. 56. The method of claim 1, wherein the mRNA is an oncogene mRNA. 57. The method of claim 1, wherein the mRNA encodes a viral protein. 58. The method of claim 14, wherein the mRNA is a cellular mRNA. 59. The method of claim 14, wherein the mRNA is an oncogene mRNA. 60. The method of claim 14, wherein the mRNA encodes a viral protein. 61. The method of claim 36, wherein the mRNA is a cellular mRNA. 62. The method of claim 36, wherein the mRNA is an oncogene mRNA. 63. The method of claim 36, wherein the mRNA encodes a viral protein.