Methylotrophic yeast producing mammalian type sugar chain
This invention is to provide a process for producing a glycoprotein comprising a mammalian type sugar chain, characterized in that the process comprises introducing an α-1,2-mannosidase gene into a methylotrophic yeast having a mutation of a sugar chain biosynthesizing enzyme gene, so that the α-1,2-mannosidase gene is expressed under the control of a potent promoter in the yeast; culturing in a medium the methylotrophic yeast cells with a heterologous gene transferred thereinto; and obtaining the glycoprotein comprising a mammalian type sugar chain from the culture. Using the newly created methylotrophic yeast having a sugar chain mutation, a neutral sugar chain identical with a high mannose type sugar chain produced by mammalian cells such as human cells, or a glycoprotein comprising such a neutral sugar chain, can be produced in a large amount at a high purity. By introducing a mammalian type sugar chain biosynthesizing gene into the above-described mutant, a mammalian type sugar chain, such as a hybrid or complex, or a protein comprising a mammalian type sugar chain can be efficiently produced.
1. A process for producing a methylotrophic yeast that produces a mammalian type sugar chain, which comprises the steps of:
1) disrupting an OCH1 gene which encodes α-1,6-mannosyl transferase and YPS1 gene which encodes Aspartic protease 3, in a methylotrophic yeast; and
2) introducing an α-1,2-mannosidase gene into the yeast and expressing it therein,
wherein the methylotrophic yeast belongs to the genus Pichia or Ogataea.
2. A process according to claim 1 , wherein the mammalian type sugar chain is represented by the following structural formula (Man 5 GlcNAc 2 ):
3. A process according to claim 1 or 2 , wherein the methylotrophic yeast is Ogataea minuta.
4. A process according to claim 1 , wherein the methylotrophic yeast is a strain from Ogataea minuta strain IFO 10746.
5. A process according to claim 1 , wherein the α-1,2-mannosidase gene is expressed under the control of a methanol-inducible promoter.
6. A process according to claim 5 , wherein the methanol-inducible promoter is a promoter of an alcohol oxidase (AOX) gene.
7. A process according to claim 6 , wherein the alcohol oxidase (AOX) gene is from Ogataea minuta.
8. A process according to claim 1 , characterized in that the α-1,2-mannosidase expressed from the α-1,2-mannosidase gene further comprises a yeast endoplasmic reticulum (ER) retention signal.
9. A process according to claim 1 , wherein the α-1,2-mannosidase gene is from Aspergillus saitoi.
10. A process according to claim 1 , which further comprises a step of transforming a heterologous gene into the yeast.
11. A process according to claim 10 , wherein the heterologous gene is transferred using an expression vector and is expressed in the yeast.
12. A process according to claim 11 , wherein the expression vector comprises a methanol-inducible promoter.
13. A process according to claim 12 , wherein the methanol-inducible promoter is a promoter of an alcohol oxidase (AOX) gene.
14. A process according to claim 13 , wherein the alcohol oxidase (AOX) gene is from Ogataea minuta.
15. A process according to claim 11 , wherein the expression vector comprises a promoter of a glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene.
16. A process according to any one of claims 10 to 15 , wherein 20% or more of N-linked sugar chains on the protein encoded by the heterologous gene is the mammalian type sugar chain represented by Structural Formula 2.
17. A process according to any one of claims 10 to 15 , wherein 40% or more of N-linked sugar chains on the protein encoded by the heterologous gene is the mammalian type sugar chain represented by Structural Formula 2.
18. A process according to any one of claims 10 to 15 , wherein 60% or more of N-linked sugar chains on the protein encoded by the heterologous gene is the mammalian type sugar chain represented by Structural Formula 2.
19. A process according to any one of claims 10 to 15 , wherein 80% or more of N-linked sugar chains on the protein encoded by the heterologous gene is the mammalian type sugar chain represented by Structural Formula 2.
20. A process according to any one of claims 10 to 15 , wherein the protein encoded by the heterologous gene is from humans.
21. A process according to any one of claims 10 to 15 , wherein the protein encoded by the heterologous gene is an antibody or a fragment thereof.
22. A methylotrophic yeast produced by a process according to claim 1 or claim 10 .
23. A process for producing a protein encoded by a heterologous gene, wherein the process comprises culturing the methylotrophic yeast produced by a process according to claim 10 in a medium to obtain the protein encoded by the heterologous gene comprising a mammalian type sugar chain from the culture.
24. A process for producing an Ogataea minuta strain, which produces a mammalian type sugar chain represented by the following structural formula (Man 5 GlcNAc 2 ):
comprising a step of disrupting OCH1 gene in the Ogataea minuta strain; and a step of disrupting a YPS1 gene in the same strain.
25. A process of claim 24 , wherein the Ogataea minuta strain is from the strain IFO 10746.
26. A process according to claim 24 , which further comprises a step of disrupting at least one gene selected from the group consisting of a URA3 gene comprising the nucleotide sequence represented by SEQ ID NO:15, an ADE1 gene comprising the nucleotide sequence represented by SEQ ID NO:27, an HIS3 gene comprising the nucleotide sequence represented by SEQ ID NO:99, and a LEU2 gene comprising the nucleotide sequence represented by SEQ ID NO:107.
27. A process according to claim 24 , which further comprises a step of disrupting at least one gene selected from the group consisting of a PEP4 gene comprising the nucleotide sequence represented by SEQ ID NO:51, a PRB1 gene comprising the nucleotide sequence represented by SEQ ID NO:57.
28. A process according to claim 27 , which further comprises a step of disrupting a KTR1 gene comprising the nucleotide sequence represented by SEQ ID NO:63 and/or an MNN9 gene comprising the sequence represented by SEQ ID NO:69.
29. A process according to any one of claims 24 to 28 , which further comprises a step of introducing and expressing an α-1,2-mannosidase gene from Aspergillus saitoi.
30. A process according to claim 29 , wherein the α-1,2-mannosidase gene is expressed from a recombinant expression vector comprising a gene expression cassette comprising:
(a) a DNA comprising a promoter of alcohol oxidase (AOX) gene which is substantially represented by SEQ ID NO:79;
(b) the α-1,2-mannosidase gene; and
(c) a terminator of alcohol oxidase (AOX) gene which is substantially represented by SEQ ID NO:80.
31. A process according to claim 24 , which further comprises a step of introducing and expressing a PDI gene.
32. A process according to claim 31 , wherein the PDI gene is a gene from Saccharomyces cerevisiae with the sequence found at GenBank Accession number M62815.
33. A process according to claim 32 , wherein the PDI gene is expressed from a recombinant expression vector comprising a gene expression cassette comprising:
(a) a DNA comprising a promoter of alcohol oxidase (AOX) gene which is substantially represented by SEQ ID NO:79;
(b) the PDI gene; and
(c) a terminator of alcohol oxidase (AOX) gene which is substantially represented by SEQ ID NO:80.
34. A process according claim 24 , which further comprises a step of introducing and expressing a heterologous gene.
35. A process according to claim 34 , wherein the heterologous gene is expressed from a recombinant expression vector comprising a gene expression cassette comprising:
(a) a DNA comprising a promoter of alcohol oxidase (AOX) gene which is substantially represented by SEQ ID NO:79;
(b) the heterologous gene; and
(c) a terminator of alcohol oxidase (AOX) gene which is substantially represented by SEQ ID NO:80.
36. A process for producing a protein encoded by a heterologous gene, which comprises culturing Ogataea minuta produced by the process of claim 34 in a medium, to obtain the protein comprising a mammalian type sugar chain encoded by the heterologous gene from the culture.
37. A process for producing an Ogataea minuta strain, which produces a mammalian type sugar chain represented by the following structural formula (Man 5 GlcNAc 2 ):
wherein the process comprises the steps of:
disrupting an OCH1 gene comprising the nucleotide sequence represented by SEQ ID NO:42 in an Ogataea minuta strain; and
disrupting a URA3 gene comprising the nucleotide sequence represented by SEQ ID NO:15 in the same strain; and
disrupting a PEP4 gene comprising the nucleotide sequence represented by SEQ ID NO:51 in the same strain; and
disrupting a PRB1 gene comprising the nucleotide sequence represented by SEQ ID NO:57 in the same strain; and
disrupting a YPS1 gene comprising the nucleotide sequence represented by SEQ ID NO:115 in the same strain.
38. A process according to claim 37 , wherein the Ogataea minuta strain is from the strain IFO 10746.
39. A process according to claim 37 or 38 , which further comprises a step of disrupting an ADE1 gene comprising the nucleotide sequence represented by SEQ ID NO:27.
40. A process according to claim 39 , which further comprises a step of disrupting a KTR1 gene comprising the nucleotide sequence represented by SEQ ID NO:63.
41. A process according to claim 40 , which further comprises a step of disrupting an HIS3 gene comprising the nucleotide sequence represented by SEQ ID NO:99.
42. A process according to claim 40 , which further comprises a step of disrupting a LEU2 gene comprising the nucleotide sequence represented by SEQ ID NO:107.
43. A process according claim 37 , which further comprises a step of introducing and expressing an α-1,2-mannosidase gene.
44. A process according to claim 43 , wherein the α-1,2-mannosidase gene is expressed from a recombinant expression vector comprising a gene expression cassette comprising:
(a) a DNA comprising a promoter of alcohol oxidase (AOX) gene which is substantially represented by SEQ ID NO:79;
(b) the α-1,2-mannosidase gene; and
(c) a terminator of alcohol oxidase (AOX) gene which is substantially represented by SEQ ID NO:80.
45. A process according to claim 37 , which further comprises a step of introducing and expressing a PDI gene from Saccharomyces cerevisiae with the sequence found at GenBank Accession number (M62815).
46. A process according to claim 45 , wherein the PDI gene (M62815) is expressed from a recombinant expression vector comprising a gene expression cassette comprising:
(a) a DNA comprising a promoter of alcohol oxidase (AOX) gene which is substantially represented by SEQ ID NO:79;
(b) the PDI gene with the sequence found at GenBank Accession number M62815; and
(c) a terminator of alcohol oxidase (AOX) gene which is substantially represented by SEQ ID NO:80.
47. A process according to claim 37 , which further comprises a step of introducing and expressing a heterologous gene.
48. A process according to claim 47 , wherein the heterologous gene is expressed from a recombinant expression vector comprising a gene expression cassette comprising:
(a) a DNA comprising a promoter of alcohol oxidase (AOX) gene which is substantially represented by SEQ ID NO:79;
(b) the heterologous gene; and
(c) a terminator of alcohol oxidase (AOX) gene which is substantially represented by SEQ ID NO:80.
49. A process for producing a protein encoded by a heterologous gene comprising a mammalian type sugar chain, wherein the process comprises culturing Ogataea minuta produced by the process of claim 47 in a medium to obtain the protein from the culture.
50. The process of claim 10 , wherein the yeast endoplasmic reticulum (ER) retention signal has the sequence of SEQ ID NO: 121.
51. The process of claim 24 , wherein the OCH1 gene has the sequence of SEQ ID NO: 42.
52. The process of claim 24 , wherein the YPS1 gene has the sequence of SEQ ID NO: 115.