Figure 4.

AML1/ETO⁺ myeloid progenitors in the CD34⁺CD38^-/lo fraction of leukemic BM. (A) Morphology of AML1/ETO⁺ myeloid colonies and AML1/ETO⁺ leukemic blast colonies derived from single AML1/ETO⁺ progenitors. These AML1/ETO⁺ colonies included colonies composed of CFU-L (a), CFU-GM (b), BFU-E (c), and CFU-Meg (d). (B) RT-PCR analysis of cells picked from single cell-derived colonies. a–d correspond to a–d in A. Note that erythrocyte and megakaryocyte colonies did not express MPO gene, which confirms that these colonies did not contain myelomonocytic components. The frequency of these AML1/ETO⁺ myeloid progenitors was up to 60% in total myeloid colonies as shown in Table 4. GAPDH, glyceraldehyde-3-phosphate dehydrogenase.