Chimeric receptor constructs and expression in erythroleukemic SKT6 cells. (A) Diagrammed are wild-type Epo, prolactin Nb2, and EGF receptors together with derived chimeric constructs composed of the human EGF receptor extracellular domain, and cytoplasmic domains of the Epo receptor (full-length EE483, C-truncation EE372) or the Nb2 receptor (EENb2). (B) SKT6 cells were transfected with pCIneo vectors encoding EE483, EE372, or EENb2, and expression of chimeric receptor transcripts in derived cell lines was assayed by Northern blotting. Hybridization was to either a human EGF receptor probe (³²P-EGFR) or to a murine Epo receptor probe (³²P-EpoR). Equivalence in RNA loading was assessed by hybridization to a GAPDH cDNA.