Method for producing dual function proteins and its derivatives

A method for producing a recombinant dual function protein from a mammalian host cell transformed with an expression vector containing cDNA encoding a dual function protein or a derivative thereof, the method comprising culturing the mammalian host cell in a culture medium supplemented with dextran sulfate, wherein the dual function protein comprises a fibroblast growth factor 21 (FGF21) mutant protein;

• a biologically active protein, or a mutant or fragment thereof;
• and an Fc region of an immunoglobulin, wherein the FGF21 mutant protein comprises at least one mutation selected from the group consisting of the mutations (1) to (7) below:
• (1) a substitution of amino acids at positions 98 to 101 from the N-terminus of a wild-type FGF21 protein with the amino acid sequence of EIRP (SEQ ID NO:
• 53);
• (2) a substitution of amino acids at positions 170 to 174 from the N-terminus of a wild-type FGF21 protein with the amino acid sequence of TGLEAV (SEQ ID NO:
• 54);
• (3) a substitution of amino acids at positions 170 to 174 from the N-terminus of a wild-type FGF21 protein with the amino acid sequence of TGLEAN (SEQ ID NO:
• 55);
• (4) a substitution of an amino acid at position 170 from the N-terminus of a wild-type FGF21 protein with the amino acid N;
• (5) a substitution of an amino acid at position 174 from the N-terminus of a wild-type FGF21 protein with the amino acid N;
• (6) a substitution of an amino acid at position 180 from the N-terminus of a wild-type FGF21 protein with the amino acid E, along with one or more mutations (1) to (5) above;
• and
• (7) a mutation of 1 to 10 amino acids for reducing immunogenicity of a wild-type FGF21 protein.