Abstract: Herein is reported a method for recombinantly producing a polypeptide in a cell comprising the step of cultivating a cell which comprises a nucleic acid encoding the polypeptide, and recovering the polypeptide from the cell or the cultivation medium, wherein each of the amino acid residues of the polypeptide is encoded by at least one codon, whereby the different codons encoding the same amino acid residue are combined in one group and each of the codons in a group is defined by a specific usage frequency within the group, whereby the sum of the specific usage frequencies of all codons in one group is 100%, and wherein the usage frequency of a codon in the polypeptide encoding nucleic acid is about the same as its specific usage frequency within its group.

Abstract: Herein is reported a method for recombinantly producing a polypeptide in a cell comprising the step of cultivating a cell which comprises a nucleic acid encoding the polypeptide, and recovering the polypeptide from the cell or the cultivation medium, wherein each of the amino acid residues of the polypeptide is encoded by at least one codon, whereby the different codons encoding the same amino acid residue are combined in one group and each of the codons in a group is defined by a specific usage frequency within the group, whereby the sum of the specific usage frequencies of all codons in one group is 100%, and wherein the usage frequency of a codon in the polypeptide encoding nucleic acid is about the same as its specific usage frequency within its group.

Abstract: The current invention describes a nucleic acid comprising in a 5? to 3? direction a) a first nucleic acid encoding a heterologous polypeptide without an in frame stop codon, b) a second nucleic acid beginning with a 5? splice donor site and terminated by a 3? splice acceptor site comprising an in frame translational stop codon and a polyadenylation signal, and c) a nucleic acid encoding i) at least a fragment of a transmembrane domain, or ii) a signal peptide for a GPI-anchor.

Abstract: The current invention describes a nucleic acid comprising in a 5? to 3? direction a) a first nucleic acid encoding a heterologous polypeptide without an in frame stop codon, b) a second nucleic acid beginning with a 5? splice donor site and terminated by a 3? splice acceptor site comprising an in frame translational stop codon and a polyadenylation signal, and c) a nucleic acid encoding i) at least a fragment of a transmembrane domain, or ii) a signal peptide for a GPI-anchor.

Abstract: The current invention reports a CHO-K1 cell, characterized in that said CHO-K 1 cell is derived from CHO-K1 cell deposited as ATCC CCL-61, grows in suspension, requires no glutamine, no insulin, and no growth factors in the cultivation medium for growth, whereby said CHO-K1 cell is not modified compared to the deposited CHO-K1 cell ATCC CCL-61 cell line by the introduction, deletion, or inactivation of a nucleic acid. Also reported are a method for obtaining said CHO-K1 cell and a method for the production of a heterologous polypeptide using such a CHO-K1 cell according to the invention.

Abstract: The current invention describes a nucleic acid comprising in a 5? to 3? direction a) a first nucleic acid encoding a heterologous polypeptide without an in frame stop codon, b) a second nucleic acid beginning with a 5? splice donor site and terminated by a 3? splice acceptor site comprising an in frame translational stop codon and a polyadenylation signal, and c) a nucleic acid encoding i) at least a fragment of a transmembrane domain, or ii) a signal peptide for a GPI-anchor.