The hEGF receptor (hEGF R)-murine Epo receptor (mEpo R) chimera, GATA-1 gene-derived transgenic expression vector, and integration of pG1-EE372 in transgenic mice. (A) Diagrammed are the wild-type (wt) murine Epo receptor and the minimal chimeric construct EE372. In EE372, the extracellular domain is that of the human EGF receptor, and the murine Epo receptor cytoplasmic domain is truncated to delete 7 of 8 sites of tyrosine (Y) phosphorylation. Also diagrammed is the GATA-1 gene-derived vector used to express EE372 in transgenic mice (pG1-EE372). uas, upstream activating sequence. pA, polyadenylation signal. (B) Southern blot analyses shown are for representative litters from f3 and f4 generations. Indexed areBgl II products from the endogenous Epo receptor gene and the pG1-EE372 transgene.