Mutant heavy chain to improve immunoglobulin production

A nucleic acid encoding a heavy chain immunoglobulin exon-intron organization genomic retained comprising a nucleic acid encoding the amino acid sequence of the C-terminal part of the CH3 domain of an immunoglobulin of the IgG class, characterized in that the dipeptide glycine-lysine at the C in said amino acid sequence of the C-terminal part of the CH3 domain is encoded by the nucleic acid ggcaaa.