Described are methods for identifying, selecting, and obtaining mammalian
cells capable of producing proteinaceous molecules having predetermined
post-translational modifications, wherein the post-translational
modifications are brought about by the mammalian cell in which the
proteinaceous molecule is expressed. Preferably, the predetermined
post-translational modifications include glycosylation. Also described
are methods for obtaining and producing proteinaceous molecules, using
mammalian cells obtainable by a method of the present invention.
Preferably, the proteinaceous molecules includes erythropoietin (EPO),
since EPO's effect depends heavily on its glycosylation pattern.
Mammalian cells that have been obtained on the basis of their ability to
produce proteins and/or post-translational modifications that are
indicative for a predetermined post-translational modification that is
desired are also provided. Preferably, the mammalian cells have neural
characteristics and properties such that significant amounts of
recombinant proteins can be produced that harbor `neural- or brain-type`
properties.