Fig. 4. Myeloid and erythroid colony forming cells are obtained from cultures of Tg^+/–Scl^–/– yolk sacs. (A) FACS analysis of yolk sacs from E9 embryos. Cell suspensions from individual yolk sacs were stained with the indicated antibodies and body remnants used for lacZ/Scl PCR genotyping. Double staining was performed using FITC-conjugated c-Kit with PE-conjugated Ter119. Quadrants were established according to values obtained using cells stained with isotype controls in the same experiment. (B) Two erythroid colonies containing diaminofluorene positive haemoglobinised cells (arrows) from Tg^+/–Scl^–/– embryos are shown. (C) PCR analysis of individual colonies from yolk sacs of the indicated genotypes. (D) May-Grunwald-Giensa staining of cytospin preparation of yolk sac haematopoietic colonies obtained from embryos of the indicated genotype. Myeloid cells were seen in colonies from both Tg^+/–Scl^–/– and Tg^+/–Scl^+/– embryos. Normoblasts (arrows) were only seen in colonies from Tg^+/–Scl^+/–.