Production of the recombinant mOSM. (A) Schematic representation of structure of the native mOSM and the epitope-tagged recombinant mOSM. (B) The recombinant mOSM (rmOSM) protein expressed in COS7 cells. Culture supernatant from COS7 cells transfected with the epitope-tagged mOSM cDNA was used to purify mOSM to homogeneity and the purified protein was analyzed by 8% to 16% polyacrylamide gel electrophoresis in the presence of SDS. Position of molecular weight standards are indicated on right by kilodalton (kD).