Methods of cloning nucleic acids or producing proteins in a low endotoxin organism
The invention provides engineered Vibrio sp. organisms that comprise a genetic modification to either or both of the lpxL and/or lpxM genes. The organisms score substantially lower in an in vitro endotoxin assay versus the unmodified or wild type organism. The organisms preserve substantially the growth rate of the corresponding unmodified organisms. The organisms can also have an exogenous nucleic acid cloned in the organism, or an exogenous nucleic acid encoding a protein, polypeptide, or peptide expressed by the organism, and optionally secreted from the organism.
1. A method of cloning a nucleic acid or of producing a protein comprising:
culturing a recombinant Vibrio sp. organism comprising:
an exogenous nucleic acid sequence for cloning by the organism, or an exogenous nucleic acid sequence encoding a heterologous protein or peptide for production by the organism;
a genetic modification selected from deletion, inactivation, or disruption of the lpxL gene or the lpxM gene, wherein the organism produces substantially less endotoxin compared to a corresponding organism not comprising the deletion, inactivation, or disruption and cultivated under the same conditions; and
wherein the recombinant Vibrio sp. organism exhibits a growth rate of at least 60% of the growth rate of the corresponding organism when cultivated under the same conditions;
wherein the organism has an endotoxin level of less than 50 EU/ml of purified lipopolysaccharide; and
harvesting the nucleic acid sequence cloned by the organism, or the protein or peptide produced by the organism.
2. The method of claim 1 , wherein the organism does not express an exogenous or endogenous lpxL or lpxM gene.
3. The method of claim 1 , wherein the organism does not comprise a deletion, inactivation, or disruption in any gene selected from the group consisting of: gutQ, kdsD, pagP, and lpxP.
4. The method of claim 1 , wherein the recombinant organism exhibits a growth rate of at least 70% of the growth rate of a corresponding unmodified Vibrio sp. organism under identical conditions.
5. The method of claim 1 , wherein the recombinant organism has an average endotoxin level of less than 1 EU/ml measured in an in vitro assay.
6. The method of claim 1 , wherein the recombinant organism has a doubling time of 55-70 minutes at 30° C.
7. The method of claim 1 , wherein the growth rate is measured over a period of 8 hours.
8. The method of claim 1 , wherein the growth rate is measured over a period of 12 hours.
9. The method of claim 1 , wherein the genetic modification is a deletion.
10. The method of claim 1 , wherein the recombinant organism is Vibrio natriegens.
11. The method of claim 1 , wherein the organism has an endotoxin level of less than 1 EU/ml, and a specific growth rate of 0.60 to 0.72 at 30° C. in LBv2 media.
12. The method of claim 1 , wherein the recombinant Vibrio sp. organism produces at least 25% of the quantity of the exogenous nucleic acid for cloning or at least 25% of the exogenous protein for expression under the same conditions as the corresponding organism when cultivated under the same conditions.
13. The method of claim 1 , wherein the quantity of exogenous nucleic acid for cloning or the protein expression is measured over a period of 12 hours.
14. The method of claim 13 , wherein the exogenous nucleic acid encodes a protein that is produced by the organism.
15. The method of claim 14 , wherein the protein produced is secreted from the cell.
16. The method of claim 1 , wherein the recombinant Vibrio sp. organism has an endotoxin level of less than 10 EU/ml measured in an in vitro assay.
17. The method of claim 16 , wherein the recombinant Vibrio sp. organism exhibits a growth rate of at least 80% of the growth rate of the corresponding organism when cultivated under the same conditions.
18. The method of claim 17 , wherein the recombinant Vibrio sp. organism has an endotoxin level of less than 1 EU/ml measured in an in vitro assay.