Abstract: The present invention is based on the finding that the combination of a specific 5?UTR polynucleotide sequence (see SEQ ID NO 1) and the hCD33 secretory leader sequence in an expression cassette for expressing a polypeptide of interest results in a surprisingly better expression level of the polypeptide of interest compared to prior art expression cassettes. Based on this finding, the present invention inter alia provides novel expression cassettes, expression vectors and methods for producing a polypeptide of interest with high yield.

Abstract: A method for selecting mammalian host cells that express a polypeptide of interest with high yield is described. The host cells comprise an expression cassette comprising at least a first polynucleotide encoding the polypeptide of interest, at least one leaky stop codon downstream of the first polynucleotide, and a second polynucleotide downstream of the leaky stop codon encoding an immunoglobulin transmembrane anchor. The host cells are cultivated to allow expression of the polypeptide of interest such that at least a portion of the polypeptide of interest is expressed as a fusion polypeptide that is displayed on the cell surface. The cells are selected based upon the presence or amount of the displayed fusion polypeptide. Also provided are methods for producing a polypeptide that employ a respective selection to identify high expressing host cells.

Abstract: The present invention is based on the finding that the combination of a specific 5?UTR polynucleotide sequence (see SEQ ID NO 1) and the hCD33 secretory leader sequence in an expression cassette for expressing a polypeptide of interest results in a surprisingly better expression level of the polypeptide of interest compared to prior art expression cassettes. Based on this finding, the present invention inter alia provides novel expression cassettes, expression vectors and methods for producing a polypeptide of interest with high yield.

Abstract: The present invention inter alia pertains to a method for generating or selecting a eukaryotic host cell expressing a desired level of a polypeptide of interest, comprising: a) providing a plurality of eukaryotic host cells comprising a heterologous nucleic acid comprising at least one cassette (Cas-POI) comprising at least a first polynucleotide (Pn-POI) encoding the polypeptide of interest, at least one stop codon downstream of the first polynucleotide, and a second polynucleotide downstream of the stop codon encoding an immunoglobulin transmembrane anchor or a functional variant thereof; b) cultivating the eukaryotic host cells to allow expression of the polypeptide of interest such that at least a portion of the polypeptide of interest is expressed as a fusion polypeptide comprising the immunoglobulin transmembrane anchor or a functional variant thereof, wherein said fusion polypeptide is being displayed on the surface of said host cell; c) selecting at least one eukaryotic host cell based upon the pre

Abstract: The application describes a method of selecting mammalian host cells that express a polypeptide of interest with high yield. The host cells contain an expression cassette with a first polynucleotide encoding a polypeptide of interest, at least one leaky stop codon located downstream of the first polynucleotide and a second polynucleotide located downstream of the leaky codon encoding an immunoglobulin transmembrane anchor comprising a cytoplasmic domain. The host cells are cultivated to allow expression of the polypeptide of interest such that some of the polypeptides of interest are expressed as fusion proteins displayed on the cell surface. High producing cells are then selected based on the presence or amount of the displayed fusion polypeptides.

Abstract: The present invention is based on the finding that the combination of a specific 5?UTR polynucleotide sequence (see SEQ ID NO 1) and the hCD33 secretory leader sequence in an expression cassette for expressing a polypeptide of interest results in a surprisingly better expression level of the polypeptide of interest compared to prior art expression cassettes. Based on this finding, the present invention inter alia provides novel expression cassettes, expression vectors and methods for producing a polypeptide of interest with high yield.

Abstract: The invention provides vector nucleic acid for expressing at least one polypeptide of interest in a mammalian cell, comprising (a) at least one expression cassette (POI) for expressing a polypeptide of interest; (b) an expression cassette (MSM) comprising a mammalian selectable marker gene; (c) an expression cassette (MASM) comprising a mammalian amplifiable, selectable marker gene; wherein the expression cassette (POI) is flanked 5? by the expression cassette (MASM), the expression cassette (MSM) is located 3? from the expression cassette (POI) and wherein the expression cassettes (MASM), (POI) and (MSM) are arranged in the same 5? to 3? orientation. Also provided are host cells, comprising said vector and methods for producing a polypeptide using respective host cells.

Abstract: The present invention is based on the finding that the combination of a specific 5?UTR polynucleotide sequence (see SEQ ID NO 1) and the hCD33 secretory leader sequence in an expression cassette for expressing a polypeptide of interest results in a surprisingly better expression level of the polypeptide of interest compared to prior art expression cassettes. Based on this finding, the present invention inter alia provides novel expression cassettes, expression vectors and methods for producing a polypeptide of interest with high yield.

Abstract: A method of screening cell clones expressing a high yield of a polypeptide of interest is provided. The method employs the consecutive use of fluorescence activated cell sorting followed by colony picking based selection of cell clones with high expression rates and high proliferation rates. Furthermore, the invention pertains to a method of producing a polypeptide of interest using cells obtained by the described screening method.

Abstract: The invention provides vector nucleic acid for expressing at least one polypeptide of interest in a mammalian cell, comprising (a) at least one expression cassette (POI) for expressing a polypeptide of interest; (b) an expression cassette (MSM) comprising a mammalian selectable marker gene; (c) an expression cassette (MASM) comprising a mammalian amplifiable, selectable marker gene; wherein the expression cassette (POI) is flanked 5? by the expression cassette (MASM), the expression cassette (MSM) is located 3? from the expression cassette (POI) and wherein the expression cassettes (MASM), (POI) and (MSM) are arranged in the same 5? to 3? orientation. Also provided are host cells, comprising said vector and methods for producing a polypeptide using respective host cells.

Abstract: The present invention inter alia pertains to a method for generating or selecting a eukaryotic host cell expressing a desired level of a polypeptide of interest, comprising: a) providing a plurality of eukaryotic host cells comprising a heterologous nucleic acid comprising at least one cassette (Cas-POI) comprising at least a first polynucleotide (Pn-POI) encoding the polypeptide of interest, at least one stop codon downstream of the first polynucleotide, and a second polynucleotide downstream of the stop codon encoding an immunoglobulin transmembrane anchor or a functional variant thereof; b) cultivating the eukaryotic host cells to allow expression of the polypeptide of interest such that at least a portion of the polypeptide of interest is expressed as a fusion polypeptide comprising the immunoglobulin transmembrane anchor or a functional variant thereof, wherein said fusion polypeptide is being displayed on the surface of said host cell; c) selecting at least one eukaryotic host cell based upon the pre

Abstract: The invention provides vector nucleic acid for expressing at least one polypeptide of interest in a mammalian cell, comprising (a) at least one expression cassette (POI) for expressing a polypeptide of interest; (b) an expression cassette (MSM) comprising a mammalian selectable marker gene; (c) an expression cassette (MASM) comprising a mammalian amplifiable, selectable marker gene; wherein the expression cassette (POI) is flanked 5? by the expression cassette (MASM), the expression cassette (MSM) is located 3? from the expression cassette (POI) and wherein the expression cassettes (MASM), (POI) and (MSM) are arranged in the same 5? to 3? orientation. Also provided are host cells, comprising said vector and methods for producing a polypeptide using respective host cells.

Abstract: The invention provides vector nucleic acid for expressing at least one polypeptide of interest in a mammalian cell, comprising (a) at least one expression cassette (POI) for expressing a polypeptide of interest; (b) an expression cassette (MSM) comprising a mammalian selectable marker gene; (c) an expression cassette (MASM) comprising a mammalian amplifiable, selectable marker gene; wherein the expression cassette (POI) is flanked 5? by the expression cassette (MASM), the expression cassette (MSM) is located 3? from the expression cassette (POI) and wherein the expression cassettes (MASM), (POI) and (MSM) are arranged in the same 5? to 3? orientation. Also provided are host cells, comprising said vector and methods for producing a polypeptide using respective host cells.