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AssigneeCalifornia Biotechnology Inc.
InventorsPeter J. Kushner, Claire L. Cofer, Jeffrey S. Friedman, Karen D. Talmadge
Estimating the term…
An expression system for recombinant production of a desired protein comprises CHO cells transformed with a DNA sequence having the desired protein coding sequence under control of the human metallothionein-II promoter. The cells can be maintained on serum-free medium and induced in the presence of an induction mediator. In addition, the system may include an enhancer element and/or a resistance-conferring gene to provide increased levels of expression. The system can process genomic as well as intronless DNA, and is capable of producing proteins which have the same characteristics as those obtained from native sources. Human growth hormone which is indistinguishable from that produced by the pituitary has been thus produced.
A regulatable expression system for a desired coding sequence, which system comprise Chinese Hamster Ovary (CHO) host cells in defined medium, which cells have been transformed with a DNA sequence comprising the metallothionein II (MT-II) promoter operably linked to said desired coding sequence, said medium being free of serum and further containing non-toxic metal ions and an induction mediator selected from the group consisting of iron ion and an iron-containing protein which is not a protein supplement.
A regulatable system for expression of a desired coding sequence which comprises mammalian host cells in serum-free medium, which cells have been transformed with a DNA sequence comprising the MT-II promoter operably linked to a desired coding sequence, wherein said serum-free medium is supplemented with an effective amount of an induction mediator selected from the group consisting of iron ion and an iron-containing protein which is not a protein supplement.
A method for obtaining regulatable expression of a desired coding sequence in mammalian host cells, said method comprising inducing the host cells which have been transformed with a DNA sequence comprising the MT-II promoter operably linked to the desired coding sequence, in serum-free medium with an effective amount of an induction mediator selected from the group consisting of iron ion and an iron-containing protein which is not a protein supplement, by adding an effective amount of zinc ion.
A regulatable system for expression of a desired coding sequence which comprises mammalian host cells transformed with a DNA sequence comprising the MT-II promoter operably linked to a desired coding sequence, in contact with a serum-free medium supplemented with an effective amount of an induction mediator selected from the group consisting of iron ion and an iron-containing protein which is not a protein supplement, and zinc ion in the range of 2.times.10.sup.-5 to 2.times.10.sup.-4 M.
Dependencies are inferred from the claim text.