KEX2 cleavage regions of recombinant fusion proteins
The invention relates to a fusion DNA construct comprising a KEX2 region comprising a KEX2 site and a KEX2 site pre-sequence immediately 5′ to the KEX2 site, a fusion polypeptide, vectors and cells comprising the fusion DNA construct, methods for producing desired proteins from filamentous fungal cells and methods for enhancing the secretion and/or cleavage of a desired protein from a cell.
1. A fusion DNA construct encoding a fusion polypeptide comprising in operable linkage from the 5′ end of said construct,
a promoter,
a first DNA molecule, which is different from any one of the second, the third, and the fourth DNA molecules, encoding a signal sequence,
a second DNA molecule, which is different from any one of the first, the third, and the fourth DNA molecules, encoding a carrier protein,
a third DNA molecule, which is different from any one of the first, the second, and the fourth DNA molecules, encoding a KEX2 region, said region comprising a KEX2 site (B 1 B 2 ) and a KEX2 site pre-sequence X4X3X2X1 immediately 5′ to the KEX2 site, wherein X4 is V, S, N, L, or K, X3 is A, V, D, W, E, or P; X2 is V, I, L or F; and X1 is E, S, T or Y, wherein the pre-sequence is not NVIS (SEQ ID NO:85; and
a fourth DNA molecule, which is different from any one of the first, the second, and the third DNA molecules, encoding a protein.
2. The fusion DNA construct of claim 1 , wherein the first DNA molecule and second DNA molecule encode a Trichoderma CBH1 signal sequence and carrier protein or a Trichoderma endoglucanase signal sequence and carrier protein.
3. The fusion DNA construct of claim 1 , wherein the first DNA molecule and second DNA molecule encode a glucoamylase signal sequence and carrier protein or an alpha amylase signal sequence and carrier protein.
4. The fusion DNA construct of claim 1 , wherein the desired protein is an enzyme.
5. The fusion DNA construct of claim 1 , wherein the desired protein is a therapeutic protein.
6. The fusion DNA construct of claim 5 , wherein the therapeutic protein is an antibody.
7. The fusion DNA construct of claim 6 , wherein the antibody is a light chain or heavy chain monoclonal antibody.
8. The fusion DNA construct of claim 1 , wherein the first DNA molecule and second DNA molecule encode a CBH I signal sequence and carrier protein and the fourth DNA molecule encodes an antibody light chain or fragment thereof.
9. The fusion DNA construct of claim 1 , wherein the first DNA molecule and second DNA molecule encode a glucoamylase signal sequence and carrier protein and the fourth DNA molecule encodes an antibody light chain or fragment thereof.
10. A host cell comprising the fusion DNA construct of claim 1 .
11. The host cell of claim 10 , wherein said host cell is a Trichoderma host cell.
12. The host cell of claim 11 , wherein the Trichoderma cell is a T. reesei cell.
13. A vector comprising the fusion DNA construct of claim 1 .
14. A host cell comprising the vector of claim 13 .
15. The host cell of claim 14 , wherein the host cell is a Trichoderma host cell.
16. A process for producing a desired protein in a filamentous fungal cell comprising:
a) obtaining a filamentous fungal host cell comprising a fusion DNA construct according to claim 1 ;
b) culturing the host cell under suitable conditions which allow for the expression and production of the desired protein; and
c) recovering the desired protein.
17. The process according to claim 16 , wherein the host cell is a Trichoderma strain.
18. The process according to claim 17 , wherein the Trichoderma cell is a T. reesei host cell.
19. The process according to claim 16 , wherein the desired protein is an immunoglobulin.
20. The process according to claim 19 , wherein the immunoglobulin is a monoclonal antibody.
21. The process according to claim 20 , wherein the monoclonal antibody is a light chain or heavy chain monoclonal antibody or fragment thereof.
22. The process according to claim 20 , wherein the host cell is a Trichoderma cell, the desired protein is a light chain antibody and the KEX2 region of the third DNA molecule is a sequence selected from VAVWKR (SEQ ID NO: 25), VAVGKR (SEQ ID NO: 26), VAVTKR (SEQ ID NO: 28), VAVVKR (SEQ ID NO: 29), VAVDKR (SEQ ID NO: 32), WAVEKR (SEQ ID NO: 40), PAVEKR (SEQ ID NO: 42), QAVEKR (SEQ ID NO: 47), HAVEKR (SEQ ID NO: 52), and VASEKR (SEQ ID NO: 79).
23. The method according to claim 18 , wherein the KEX2 region of the third DNA molecule is a sequence selected from VAVWKR (SEQ ID NO: 25), VAVGKR (SEQ ID NO: 26), VAVTKR (SEQ ID NO: 28), VAVVKR (SEQ ID NO: 29), VAVDKR (SEQ ID NO: 32), WAVEKR (SEQ ID NO: 40), PAVEKR (SEQ ID NO: 42), QAVEKR (SEQ ID NO: 47), HAVEKR (SEQ ID NO: 52), and VASEKR (SEQ ID NO: 79).