Compositions of and methods for in vitro viral genome engineering
The present disclosure relates to a method of in vitro engineering of nucleic acids. This disclosure further relates to in vitro engineering of viral genomes and to the improvement of viral properties by in vitro genomic engineering of viral genomes. Specifically, the disclosure relates to in vitro viral genomic digestion using RNA-guided Cas9, the assembly of a recombinant genome by the insertion of a DNA or RNA fragment into the digested viral genome and transformation of a host cell with the recombinant genome. This method also related to in vitro engineering for error correction of nucleic acids.
1. A method for generating a recombinant phage that expresses two or more payloads, the method comprising:
(a) providing a first viral genome from a first phage; and
(b) generating an engineered viral genome by
(1) in vitro digesting a region of the first viral genome using an endonuclease; and
(2) assembling at least one fragment of the digested first viral genome with at least one repair nucleic acid molecule,
to generate a second viral genome comprising at least one modification compared to the first and the second viral genome, upon introduction into a host cell, produces viral particles with two or more payloads selected from the group consisting of a DNase, an exopolysaccharide (EPS) depolymerase, and one or more surfactant phenol soluble modulin (PSM); and
(c) introducing said second viral genome into a host cell capable of producing viral particles, thereby producing an engineered recombinant phage.
2. The method of claim 1 , further comprising:
(3) repeating steps (a)-(b) in one or more iterations.
3. The method of claim 1 , wherein each payload independently changes one or more of the host range, viral lytic cycle, adsorption, attachment, injection, replication and assembly, lysis, burst size, immune evasion, immune stimulation, immune deactivation, biofilm dispersion, bacterial phage resistance, bacterial antibiotic sensitization, modulation of virulence factors, and targeted host genome digestion or editing of the recombinant phage as compared to the first phage.
4. The method of claim 1 , wherein the first viral genome is isolated from viral particles.
5. The method of claim 1 , wherein the first viral genome or the at least one repair nucleic acid molecule is synthesized de novo.
6. The method of claim 5 , wherein de novo synthesis comprises combining chemically synthesized nucleic acid molecules, PCR-amplified nucleic acid sequences, digested fragments of isolated nucleic acid molecules, or any combination thereof.
7. The method of claim 5 , wherein the first viral genome or the at least one repair nucleic acid molecule is amplified prior to in vitro digestion.
8. The method of claim 1 , wherein the first viral genome is at least 3 kb, at least 10 kb, at least 18 kb, at least 25 kb, at least 30 kb, at least 40 kb, at least 50 kb, at least 70 kb, at least 100 kb, at least 125 kb, at least 150 kb, at least 200 kb, or at least 300 kb.
9. The method of claim 1 , wherein the assembly is performed in vitro or in vivo.
10. The method of claim 9 , wherein the assembly is performed in vitro with a mixture comprising:
(a) an isolated 5′ to 3′ exonuclease that lacks 3′ exonuclease activity;
(b) an isolated non-strand-displacing DNA polymerase with 3′ exonuclease activity, or a mixture of said DNA polymerase with a second DNA polymerase that lacks 3′ exonuclease activity;
(c) an isolated ligase; and
(d) a mixture of dNTPs, under conditions that are effective for insertion of the fragment into the digested viral nucleic acid to form a recombinant nucleic acid comprising the engineered viral genome.
11. The method of claim 1 , wherein the endonuclease is an RNA-guided nuclease.
12. The method of claim 11 , further comprising at least one guiding RNA.
13. The method of claim 12 , wherein the RNA-guided nuclease is Cas9 or a Cas9 derived enzyme, and wherein the at least one guiding RNA comprises 1) a chimeric gRNA or 2) a crRNA and tracrRNA.
14. The method of claim 1 , wherein the endonuclease is heat inactivated or removed prior to assembly.
15. The method of claim 1 , wherein the in vitro digestion further comprises spermidine.
16. The method of claim 1 , wherein introducing comprises transforming the engineered viral genome into a host cell.
17. The method of claim 1 , further comprising using an in vitro packaging kit for packaging of the engineered viral genome into viral particles.
18. A method of engineering a recombinant nucleic acid sequence comprising:
(a) providing a nucleic acid;
(b) in vitro digesting a region of the nucleic acid using an RNA-guided nuclease; and
(c) assembling a recombinant nucleic acid by insertion of a DNA fragment into the digested nucleic acid, wherein assembling is performed in vitro in a single vessel with a mixture of components comprising:
(i) an isolated 5′ to 3′ exonuclease that lacks 3′ exonuclease activity;
(ii) an isolated non-strand-displacing DNA polymerase with 3′ exonuclease activity, or a mixture of said DNA polymerase with a second DNA polymerase that lacks 3′ exonuclease activity;
(iii) an isolated ligase; and
(iv) a mixture of dNTPs;
under conditions that are effective for insertion of the fragment into the digested nucleic acid to form a recombinant nucleic acid sequence.
19. The method of claim 18 , wherein the RNA-guided nuclease is Cas9 or a Cas9 derived enzyme.
20. The method of claim 18 , wherein the RNA-guided nuclease is heat inactivated or removed prior to assembly.
21. The method of claim 18 , further comprising:
(d) transforming the recombinant nucleic acid into a host cell.
22. The method of claim 18 , wherein the nucleic acid is a plasmid isolated from a host cell.
23. The method of claim 22 , wherein the plasmid is at least 6 kb.
24. The method of claim 22 , wherein the plasmid is at least 10 kb.
25. The method of claim 22 , wherein the plasmid is at least 15 kb.
26. The method of claim 22 , wherein the plasmid is at least 20 kb.
27. The method of claim 1 , wherein the two or more payloads comprise a DNase.
28. The method of claim 1 , wherein said two or more payloads comprise an EPS depolymerase.
29. The method of claim 1 , wherein said two or more payloads comprise a phenol soluble modulin.
30. The method of claim 29 , wherein said phenol soluble modulin is selected from the group consisting of PSMα, PSMα3, and PSMβ32.