Improvement in hemoglobinization but persistent hemolysis in EKLF^−/− embryos.

(A) Photographs of a litter of E15 embryos (magnification ×10). The EKLF genotype (± and −/− ) and the presence of the transgene (R) are indicated above each photograph. (B) Slight improvement in the crimson hue of an EKLF^−/−fetal liver that harbors the μLCR− ^Aγ⁺transgene (−/−R) compared to 1 that does not (−/−). (C) Slight improvement in the benzidine staining of EKLF−/− fetal liver cells that harbor the transgene (−/−R) compared with those that do not (−/−). Arrows indicate benzidine-positive cells. (D) May-Gruenwald-Giemsa (MGG) stained cytocentrifuge specimens of the blood from the same 3 embryos depicted in A indicating some rescue in hemoglobinization of fetal liver-derived erythroid cells. However, morphologically abnormal nucleated erythrocytes persist. y, yolk sac derived nucleated red cells; PN, pronormoblast; en, early normoblast; ln, late normoblast; r, fetal liver-derived enucleate red cell. Arrows indicate occasional enucleate red cells in EKLF^−/− , μLCR−^Aγ ⁺fetal liver samples.