The murine EPOR is not required for Friend virus-induced erythroblastosis. (A) Southern blot of genomic DNA from the progeny of Epor^-/-;Tg(EPOR) × Balb/cByJ Epor^+/- mice. The parents contained different targeted mutations of the Epor,^24,25  which are indicated by the arrowheads (Epor KO-1 and Epor KO-2). Bands corresponding to the germ-line band and the human EPOR transgene (Tg(EPOR)), are indicated. Genotypes: lane 1, Epor^+/-;Tg(EPOR); lane 2, wild type; lane 3, Epor^-/-;Tg(EPOR). (B) Spleen weights of FVA-infected mice in grams. Genotypes are indicated at the bottom. Epor^+/+ and Epor^+/- genotypes are grouped together as (+/^). Error bars represent standard deviations.