| abstract |
A eukaryotic expression system comprising: - at least one first polynucleotide encoding at least one vitamin metabolic protein under the control of at least one first regulatory sequence, and - under the control of at least one second regulatory sequence, at least one restriction enzyme cleavage site and / or at least one second polynucleotide encoding at least one product of interest, - wherein the at least one vitamin metabolic protein is a vitamin transport protein, and wherein said protein vitamin transport is THTR-1, THTR-2, TPK, TPC and / or SMVT (sodium-dependent multivitamin transporter). |