Protein-responsive RNA control devices and uses thereof
The invention described herein relates to an RNA-based control device that senses the presence and/or concentration of at least one protein ligand, preferably through its protein-binding aptamer domain, and regulates a target gene expression through alternative splicing of the target gene in which the RNA-based control device is integrated. The device has uses in therapeutic as well as diagnostic applications.
1. An RNA capable of undergoing alternative splicing in an actuator module, comprising:
(1) an input module comprising an aptamer that binds a protein ligand not associated with splicing regulation;
(2) an output module comprising a coding sequence for a functional gene product; and,
(3) the actuator module operably connected to the input module and the output module, and said actuator module comprising a sequence capable of undergoing alternative splicing,
wherein the aptamer is integrated into the actuator module and into an intron, and is integrated between 1 and 50 nt away from a regulatory sequence for alternative splicing, and wherein binding of the protein ligand to the aptamer enhances or inhibits the function of the regulatory sequence to alter alternative splicing pattern and expression of the coding sequence.
2. The RNA of claim 1 , wherein the regulatory sequence is a 5′ splice site (5′ ss), a 3′ splice site (3′ ss), a splicing branch point, a polypyrimidine tract, a splicing enhancer, or a splicing suppressor.
3. The RNA of claim 1 , wherein the protein ligand is endogenous to a cell.
4. The RNA of claim 1 , wherein the protein ligand contains a nuclear localization sequence.
5. The RNA of claim 1 , wherein expressing of the protein ligand or lack thereof is associated with an abnormal or a differentiated state of a cell.
6. The RNA of claim 5 , wherein the abnormal state is associated with a disease condition, over-proliferation of a cell, drug resistance, or abnormal apoptosis.
7. The RNA of claim 1 , wherein the sequence capable of undergoing alternative splicing is a minigene comprising a first exon, a first intron, a second exon, a second intron, and a third exon in tandem, wherein the second exon is included in one alternative splicing product, but is excluded in a different alternative splicing product.
8. The RNA of claim 7 , wherein the second exon comprises a sequence element that inhibits the expression of a product encoded by the coding sequence.
9. The RNA of claim 8 , wherein the sequence element is a translation stop codon, a transcription terminator, a secondary structure that inhibits ribosome function, or a self-cleaving ribozyme.
10. The RNA of claim 1 , wherein the aptamer is integrated between 2 and 30 nt away from the regulatory sequence.
11. The RNA of claim 1 , wherein the aptamer is integrated between 2 and 20 nt away from the regulatory sequence.
12. The RNA of claim 1 , wherein the output module is 3′ to the actuator module.
13. The RNA of claim 1 , comprising modified nucleotide and/or sugar-phosphate backbone.
14. The RNA of claim 1 , wherein the coding sequence encodes a reporter protein, a transcription factor, an enzyme, a proapoptotic protein, or an anti-apoptotic protein.
15. An RNA capable of undergoing alternative splicing in an actuator module, comprising:
(1) a first input module comprising a first aptamer that binds a first protein ligand not associated with splicing regulation, and integrated into an intron, at or near a first regulatory sequence for alternative splicing;
(2) a second input module comprising a second aptamer that binds a second protein ligand, and integrated into the intron, at or near a second regulatory sequence for alternative splicing;
(3) an output module comprising a coding sequence; and,
(4) the actuator module operably connected to the first and second input modules and the output module, and said actuator module comprising a sequence capable of undergoing alternative splicing,
wherein binding of the first and second protein ligands to their respective aptamers synergistically modulates alternative splicing through modulating the function of the respective regulatory sequences.
16. The RNA of claim 15 , wherein the first and second aptamers are different.
17. The RNA of claim 15 , wherein the first and second protein ligands are different.
18. A method of producing a desired RNA capable of undergoing alternative splicing in an actuator module, the method comprising:
(1) providing a candidate RNA comprising:
(a) an input module comprising an aptamer that binds a protein ligand not associated with splicing regulation;
(b) an output module comprising a coding sequence; and,
(c) the actuator module operably connected to the input module and the output module,
wherein the aptamer is integrated into the actuator module and into an intron, and is integrated at an integration site that is between 1-50 nt away from a regulatory sequence for alternative splicing;
(2) contacting each RNA with the protein ligand, under a condition that permits binding of the protein ligand to the aptamer;
(3) determining whether binding of the protein ligand to the aptamer integrated at the integration site enhances or inhibits the function of the regulatory sequence in alternative splicing;
(4) isolating the candidate RNA as the desired RNA, if binding of the protein ligand to the aptamer either enhances or inhibits the function of the regulatory sequence in alternative splicing.
19. The method of claim 18 , further comprising replacing the aptamer with a different aptamer, and repeating steps (2)-(4).
20. The method of claim 19 , wherein the different aptamer binds to a different protein ligand.