Conjugative plasmids and methods of use thereof
The present invention provides novel C. botulinum conjugatively transmissible plasmids and methods of use thereof. Specifically, described herein are novel, conjugatively transmissible clostridial plasmids which are capable of being transferred among and between clostridial species. The novel plasmids of the present invention therefore permits the delivery of heterologous clostridial genes into a clostridial host, such as C. botulinum , and the expression of genes of interest in that host, including clostridial toxins and the nontoxigenic components of the toxin complex, toxin fragments, or antigenic portions thereof, in a way both that ensures abundant expression and facilitates purification. Furthermore, toxins with altered structures, chimeric, hybrid toxins, and other toxin derivatives valuable in medicine could be synthesized in this system.
1. A method of conjugatively transferring a gene of interest into a recipient Clostridium strain, the method comprising
(a) conjugatively transferring a plasmid comprising
(i) a native plasmid of a donor C. botulinum strain capable of being conjugatively transferred into a recipient Clostridium strain, wherein the plasmid comprises a selective marker and wherein the plasmid is selected from the group consisting of pCLJ (SEQ ID NO: 2), pCLL (SEQ ID NO: 3), pBot81E-1133, and pCLD (SEQ ID NO:4); and
(ii) a nucleotide sequence of a gene of interest capable of being expressed in the recipient Clostridium strain, wherein the gene is not native to the donor C. botulinum strain,
wherein the gene of interest is incorporated into the plasmid of the donor C. botulinum strain by being operably joined to a promoter effective in Clostridium strain, and
wherein the gene of interest is expressed in the recipient Clostridium strains.
2. The method of claim 1 , wherein the donor C. botulinum strain is selected from C. botulinum serotypes A, B, C, D, E, F or G.
3. The method of claim 1 , wherein the donor C. botulinum strain is selected from C. botulinum strains Ba, Ab, Bf, Af or A(B).
4. The method of claim 1 , wherein the gene of interest is a gene for expressing clostridial toxins, toxin fragments, or antigenic portions thereof.
5. The method of claim 1 , wherein the promoter is a NTNH promoter.
6. The method of claim 1 , wherein the donor Clostridium strain and the recipient Clostridium strain are the same species.
7. A method of conjugatively transferring a gene of interest into a recipient Clostridium strain, the method comprising conjugatively transferring a plasmid comprising
(i) a native plasmid of a donor C. botulinum strain capable of being conjugatively transferred into a recipient Clostridium strain, wherein the plasmid comprises a selective marker and wherein the plasmid is selected from the group consisting of pBotCDC-A3 (SEQ ID NO: 1), pCLJ (SEQ ID NO: 2), pCLL (SEQ ID NO: 3), pBot81E-1133, and pCLD (SEQ ID NO:4), and
(ii) a nucleotide sequence of a gene of interest capable of being expressed in the recipient Clostridium strain, wherein the gene is not native to the donor C. botulinum strain,
wherein the gene of interest is incorporated into the plasmid of the donor C. botulinum strain by being operably joined to a promoter effective in Clostridium strains, wherein the gene of interest is expressed in the recipient Clostridium strain, and wherein the donor Clostridium strain and the recipient Clostridium strain are different species.
8. A method of conjugatively transferring a gene of interest into a recipient Clostridium strain, the method comprising conjugatively transferring a plasmid comprising
(i) a native plasmid of a donor C. botulinum strain capable of being conjugatively transferred into a recipient Clostridium strain, wherein the plasmid comprises a selective marker and wherein the plasmid is selected from the group consisting of pBotCDC-A3 (SEQ ID NO: 1), pCLJ (SEQ ID NO: 2), pCLL (SEQ ID NO: 3), pBot81E-1133, and pCLD (SEQ ID NO:4), and
(ii) a nucleotide sequence of a gene of interest capable of being expressed in the recipient Clostridium strain, wherein the gene is not native to the donor C. botulinum strain,
wherein the gene of interest is incorporated into the plasmid of the donor C. botulinum strain by being operably joined to a promoter effective in Clostridium strains, wherein the gene of interest is expressed in the recipient Clostridium strain, and wherein the recipient Clostridium strain is toxic.
9. A method of conjugatively transferring a gene of interest into a recipient Clostridium strain, the method comprising conjugatively transferring a plasmid comprising
(i) a native plasmid of a donor C. botulinum strain capable of being conjugatively transferred into a recipient Clostridium strain, wherein the plasmid comprises a selective marker and wherein the plasmid is selected from the group consisting of pBotCDC-A3 (SEQ ID NO: 1), pCLJ (SEQ ID NO: 2), pCLL (SEQ ID NO: 3), pBot81E-1133, and pCLD (SEQ ID NO:4), and
(ii) a nucleotide sequence of a gene of interest capable of being expressed in the recipient Clostridium strain, wherein the gene is not native to the donor C. botulinum strain,
wherein the gene of interest is incorporated into the plasmid of the donor C. botulinum strain by being operably joined to a promoter effective in Clostridium strains, wherein the gene of interest is expressed in the recipient Clostridium strain, and wherein the recipient Clostridium strain is proteolytic.
10. The method of claim 1 wherein the recipient Clostridium strain is LNT01 or Hall A-Hyper.
11. The method of claim 1 wherein the plasmid that is conjugative transferred is larger than 150 kb.
12. The method of claim 1 wherein the conjugative transfer plasmid is further genetically tagged with an antibiotic resistance gene for conferring resistance to erythromycin, tetracycline, chloramphenicol or thiamphenicol.
13. The method of claim 1 wherein the recipient Clostridium strain is nontoxic.
14. The method of claim 1 wherein the recipient Clostridium strain is nonproteolytic.