Runx1-rescued cells generate hematopoietic colonies. Colony formation of the Runx1-rescued cells from Notch1-null embryos. The rescued cells were harvested at day 12 and plated into MethoCult GF M3434 medium. (A) Representative hematopoietic colonies at day 7 are shown. Mix indicates mixed colony; GM, granulocyte/macrophage colony; and E, erythroid colony. Morphology of the colonies (top panels); original magnification, × 100. Wright-Giemsa–stained cytospin preparation of corresponding cell populations (bottom panels); original magnification, × 600. (B) Photographs of representative colonies. Original magnification, × 3. (C) The total number of colonies and the frequencies of different kinds of colonies. The results show the mean values of 5 independent experiments, each in duplicate, with standard deviations for the total colony numbers. Data were statistically analyzed by 2-tailed, unequal-variance t test.