Abstract: The present invention concerns a method of identifying genetically modified mammalian cells using a mutated protein-tyrosine kinase receptor (PTKR) as a selectable marker in mammalian cells. Particularly preferred mutated PTKR selective markers are mutated epidermal growth factor receptor (EGFR) family members, and muscle specific tyrosine kinase receptor (MuSK-R) family members. Further a method for the immunoselection of transduced mammalian cells is disclosed comprising retrovirally transducing mammalian cells with a nucleic acid sequence encoding a mutated EGFR, incubating the transduced cells with a marked antibody which recognizes and binds specifically to the mutated PTKR, and identifying the marked transduced cells.

Abstract: The present invention concerns a method of using a muscle specific tyrosine kinase receptor molecule (MuSK-R) or a mutated MuSK-R (mMuSK-R) thereof as a selectable marker in mammalian cells, particularly human cells. Preferred markers are mMuSK-Rs incapable of signal transduction and preferably molecules wherein the intracellular domain has been modified by deletion of the signaling region. The invention also relates to a method of identifying genetically modified mammalian cells including introducing a mMuSK-R into a target cell as a selectable marker. Further a method for the immunoselection of transduced mammalian cells is disclosed comprising identifying the transduced cells by incubation of the cells with an antibody which recognizes and binds specifically to a MuSK-R or mMuSK-R thereof.