Method of suppressing gene transcription through histone lysine methylation
The present invention relates to methods of suppressing the transcriptional expression of one or more genes by methylating the chromatin histone proteins of the one or more genes. Specifically, a viral SET domain histone lysine mehtyltransferase (vSET or vSET-like protein) methylates lysine 27 of a gene's histone protein 3 (H3-K27) thereby suppressing the transcription of the gene.
1. A pharmaceutical composition for human administration comprising a purified fusion protein comprising a Chlorella virus SET domain of a viral histone lysine methyltransferase protein (vSET), or of a vSET-like protein, fused to a protein that binds to a target gene, in a pharmaceutically acceptable carrier.
2. The composition of claim 1 , wherein the vSET protein comprises an amino acid sequence defined by SEQ ID NO:2.
3. The composition of claim 1 , wherein the purified fusion protein further comprises a nuclear localization signal.
4. The composition of claim 3 , wherein the nuclear localization signal is a Lys-Arg-Met-Arg (KRMR) (SEQ ID NO:3) peptide.
5. The composition of claim 1 , wherein the Chlorella virus SET domain of a viral histone lysine methyltransferase protein (vSET) or of a vSET-like protein is covalently linked to the protein that binds to a target gene.
6. The composition of claim 1 , wherein the target gene is a cytokine, an oncogenic gene, a homeodomain gene, a transcription factor, a receptor, a regulatory gene, a cell cycle regulating protein or a viral replication gene.
7. The composition of claim 6 , wherein the target gene is a cytokine selected from the group consisting of TNF-α, TGF-β, IFN-γ, IL-2, IL-10 and any combination thereof.
8. The composition of claim 6 , wherein the target gene is an oncogenic gene selected from the group consisting of MDM2, Src tyrosine kinases, Ras kinases, receptor tyrosine kinases, epidermal growth factor receptors (EGFRs), platelet-derived growth factor receptors (PDGFRs), vascular endothelial growth factor receptors (VEGFRs) and any combination thereof.
9. The composition of claim 6 , wherein the target gene is a homeodomain gene selected from the group consisting of HOXA2, HOXA5, HOXA7, HOXA9, HOXB9, HOXC6, HOXC8, HOXD8, Hey1 and any combination thereof.
10. The composition of claim 6 , wherein the target gene is a transcription factor selected from the group consisting of myc, NF-κB and combination thereof.
11. The composition of claim 6 , wherein the target gene is a receptor selected from the group consisting of an androgen receptor, a retinoic acid receptor (RAR), a retinoic acid x receptor (RXR) and any combination thereof.
12. The composition of claim 6 , wherein the target gene is a regulatory gene selected from the group consisting of E cadherin, M50/Beta-catenin and combination thereof.
13. The composition of claim 6 , wherein the target gene is a cell cycle regulating protein selected from the group consisting of any cyclin D proteins and any combination thereof.
14. The composition of claim 6 , wherein the target gene is a HIV transcriptional activator protein tat.
15. The composition of claim 1 , wherein the protein that binds to a target gene is selected from the group consisting of transcription factors, enhancer proteins, suppressor proteins, the DNA binding domains thereof and any combination thereof.
16. The composition of claim 15 , wherein the protein that binds to a target gene is selected from the group consisting of NF-kB, HOXC6, HOXC8, the DNA binding domains thereof and any combination thereof.
17. A pharmaceutical composition for selectively inhibiting transcriptional expression of a target gene in a subject in need thereof, comprising:
i) a purified fusion protein comprising:
a) a Chlorella virus SET domain of a viral histone lysine methyltransferase protein (vSET) or of a vSET-like protein, covalently linked to
b) a protein that binds to the target gene, and
ii) a pharmaceutically acceptable carrier.