Signal peptide, and use thereof for producing recombinant proteins

1. A method for producing a recombinant polypeptide of interest in an expression system, comprising introducing a signal peptide into the expression system, said signal peptide comprising at least 12 amino acids and having the sequence of formula (I):

(X1) i X2X3X4SX5X6X7  (I),

wherein

X1 is a peptide containing from 3 to 6 amino acids, and i is 0 or 1,

X2 is a peptide containing from 3 to 9 hydrophobic amino acids,

X3 is a peptide containing from 3 to 5 amino acids, said peptide comprising at least 3 contiguous or non-contiguous leucines,

X4 is a peptide containing from 2 to 5 amino acids selected from the group consisting of Ala, Thr, Ser, Gln, Ile, and Met,

X5 is Ala or Val,

X6 is Asn or His, and

X7 is Ala or Cys,

provided that:

when said signal peptide originates from a natural precursor of a specific protein, said polypeptide of interest is different from said protein, and

irrespective of the polypeptide of interest which can be bound to one of said signal peptides in order to be secreted in the extracellular medium.

2. The method according to claim 1 , wherein the quantity of the secreted polypeptide corresponds at least to the quantity of said secreted polypeptide using its natural signal peptide.

3. The method according to claim 1 , wherein said signal peptide has the sequence of formula (II):

M(X1) i X2X3X4SX5X6X7  (II).

4. The method according to claim 3 , wherein the peptide X3 comprises at least 3 contiguous leucines.

5. The method according to claim 3 , wherein the peptide X3 comprises at least 3 non-contiguous leucines.

6. The method according to claim 3 , wherein

i=1,

X3 is a peptide constituted by leucines, represented by Ln, wherein n is the number of leucines, n being a number greater than or equal to 3,

X4 is a peptide containing from 2 to 5 amino acids selected from the group consisting of Ala, Thr, Ser, Gln, and Ile,

X5 is Ala,

X6 is Asn, and

X7 is Ala,

said peptide comprising the following sequence of amino acids:

X1 X2 Ln X4 S A X6 A.

7. The method according to claim 3 , wherein

i=1,

X3 is a peptide comprising 3 non-contiguous leucines, and 2 of said leucines are separated by another hydrophobic amino acid selected from the group consisting of Gly, Ala, Val, Ile, Pro, Phe, and Trp,

X4 is a peptide containing from 2 to 5 amino acids selected from the group consisting of Ala, Thr, Ser, Gln, and Ile,

X5 is Val,

X6 is His, and

X7 is Cys,

said peptide comprising the following sequence of amino acids:

X1 X2 X3 X4 S V H C.

8. The method according to claim 1 , wherein the expression system is a higher eukaryotic cell line.

9. The method according to claim 8 , wherein the higher eukaryotic cell line is selected from the group consisting of SP2/0, SP2/0-Ag 14, NS0, IR983F, Namalwa, Wil-2, Jurkat, Molt-4, PER.C6, HEK293T/17, HEK293, HEK-293.2, Vero, Cos-1, Cos-7, BHK, CHO-K-1, CHO-Lec1, CHO-Lec10, CHO-Lec13, CHO Pro-5, CHO DX B11, CHO DG44, EBx, EB66K6H6, P3X63Ag8.653, YB2/0, CHO-S, and HEK-293F.

10. The method according to claim 1 , wherein the expression system is a transgenic animal, selected from the group consisting of goats, sheep, bisons, camels, cows, pigs, rabbits, horses, rats, mice or and llamas.

11. The method according to claim 1 , wherein the recombinant polypeptide of interest is selected from the group consisting of a hormone, an enzyme, an immunoglobulin chain, a whole immunoglobulin, or any fragment from an immunoglobulin, a protein involved in the immune response, cytokines, interleukins, complement factors, a chimeric protein, therapeutic proteins, coagulation factors, extracellular matrix proteins, and soluble receptors.

12. The method according to claim 1 , wherein the primary and secondary structures of said recombinant polypeptide are identical to those of the secreted polypeptide using its natural signal peptide.

13. A signal peptide comprising at least 12 amino acids and having the sequence of formula III:

X1X2X3X4SX5X6X7  (III),

wherein

X1 is a peptide containing from 3 to 6 amino acids,

X2 is a peptide containing from 3 to 9 hydrophobic amino acids,

X3 is a peptide containing from 3 to 5 amino acids, said peptide comprising at least 3 contiguous leucines,

X4 is a peptide containing from 2 to 5 amino acids selected from the group consisting of Ala, Thr, Ser, Gln, and Ile,

X5 is Ala,

X6 is Asn, and

X7 is Ala.

14. The signal peptide of claim 13 , having the sequence of formula (IV):

MX1X2X3X4SX5X6X7  (IV).

15. The signal peptide according to claim 13 , wherein the signal peptide comprises or consists of the sequence of amino acids: MRWSWIFLLLLSITSANA (SEQ ID NO: 1).

16. An isolated nucleic acid encoding the signal peptide according to claim 13 .

17. The nucleic acid according to claim 16 , encoding the peptide MRWSWIFLLLLSITSANA (SEQ ID NO: 1).

18. A precursor of a recombinant polypeptide of interest, wherein the precursor has a signal peptide comprising at least 12 amino acids and having the sequence of formula (I):

(X1) i X2X3X4SX5X6X7,  (I)

wherein

X1 is a peptide containing from 3 to 6 amino acids, and i is 0 or 1,

X2 is a peptide containing from 3 to 9 hydrophobic amino acids,

X3 is a peptide containing from 3 to 5 amino acids, said peptide comprising at least 3 contiguous or non-contiguous leucines,

X4 is a peptide containing from 2 to 5 amino acids selected from the group consisting of Ala, Thr, Ser, Gln, Ile, and Met,

X5 is Ala or Val,

X6 is Asn or His, and

X7 is Ala or Cys,

provided that when said signal peptide originates from a natural precursor of a specific protein, said polypeptide of interest is different from said protein, and

irrespective of the polypeptide of interest which can be bound to one of said signal peptides in order to be secreted in the extracellular medium.

19. The precursor of a recombinant polypeptide of interest according to claim 18 , wherein the signal peptide has the sequence of formula III:

X1X2X3X4SX5X6X7  (III),

wherein

X1 is a peptide containing from 3 to 6 amino acids,

X2 is a peptide containing from 3 to 9 hydrophobic amino acids,

X3 is a peptide containing from 3 to 5 amino acids, said peptide comprising at least 3 contiguous leucines,

X4 is a peptide containing from 2 to 5 amino acids selected from the group consisting of Ala, Thr, Ser, Gln, and Ile,

X5 is Ala,

X6 is Asn, and

X7 is Ala.

20. The precursor of a recombinant polypeptide of interest according to claim 18 , wherein the signal peptide comprises the following sequence of amino acids:

X1 X2 X3 X4 S V H C,

wherein

X1 is a peptide containing from 3 to 6 amino acids,

X2 is a peptide containing from 3 to 9 hydrophobic amino acids,

X3 is a peptide comprising 3 non-contiguous leucines, wherein 2 of said leucines are separated by another hydrophobic amino acid selected from the group consisting of Gly, Ala, Val, Ile, Pro, Phe, and Trp,

X4 is a peptide containing from 2 to 5 amino acids selected from the group consisting of Ala, Thr, Ser, and Gln,

provided that when said signal peptide originates from a natural precursor of a specific protein, said polypeptide of interest is different from said protein.

21. The precursor of a recombinant polypeptide of interest according to claim 18 , wherein said recombinant polypeptide of interest is selected from the group consisting of a hormone, an enzyme, an immunoglobulin chain, a whole immunoglobulin, any fragment derived from an immunoglobulin, a protein involved in the immune response, cytokines, interleukins, complement factors, a chimeric protein, therapeutic proteins, coagulation factors, extracellular matrix proteins, and soluble receptors.

22. An isolated nucleic acid encoding the precursor of a recombinant polypeptide of interest according to claim 18 .

23. A vector containing the nucleic acid according to claim 22 .

24. A method for producing a recombinant polypeptide of interest, the method comprising:

the addition of a nucleic acid encoding a signal peptide comprising at least 12 amino acids and having the sequence of formula (I):

(X1) i X2X3X4SX5X6X7  (I),

wherein

X1 is a peptide containing from 3 to 6 amino acids, and i is 0 or 1,

X2 is a peptide containing from 3 to 9 hydrophobic amino acids,

X3 is a peptide containing from 3 to 5 amino acids, said peptide comprising at least 3 contiguous or non-contiguous leucines,

X4 is a peptide containing from 2 to 5 amino acids selected from the group consisting of Ala, Thr, Ser, Gln, Ile, and Met,

X5 is Ala or Val,

X6 is Asn or His, and

X7 is Ala or Cys,

to the 5′ end of a nucleic acid encoding a recombinant polypeptide of interest, to obtain a nucleic acid encoding the precursor of said recombinant polypeptide of interest, provided that when said signal peptide originates from a natural precursor of a specific protein, said polypeptide of interest is different from said protein,

cloning the nucleic acid encoding the precursor obtained in the previous stage into an expression vector, to obtain a vector capable of expressing the precursor of said recombinant polypeptide of interest,

transfecting cells of a higher eukaryotic cell line with said vector comprising said nucleotide sequence and expressing said nucleotide sequence, and

recovering the recombinant polypeptide of interest secreted in the culture medium.

25. The method according to claim 24 , wherein the eukaryotic cell line is selected from the group consisting of SP2/0, SP2/0-Ag 14, NS0, IR983F, Namalwa, Wil-2, Jurkat, Molt-4, PER.C6, HEK293T/17, HEK293, HEK-293.2, Vero, Cos-1 or Cos-7, BHK, CHO-K-1, CHO-Lec1, CHO-Lec10, CHO-Lec13, CHO Pro-5, CHO DX B11, CHO DG44, EBx EB66K6H6, P3X63Ag8.653, YB2/0, CHO-S and HEK-293F.

26. The method according to claim 25 , wherein the recombinant polypeptide of interest is selected from the group consisting of a hormone, an enzyme, an immunoglobulin chain, a whole immunoglobulin, any fragment derived from an immunoglobulin, a protein involved in the immune response, cytokines, interleukins, complement factors, a chimeric protein, therapeutic proteins, coagulation factors, extracellular matrix proteins, and soluble receptors.