Increased Expression of AML1during Retinoic-Acid-Induced Differentiation of U937 Cells

The AML1gene on chromosome 21 is disrupted in the (8;21)(q22;q22) and (3;21)(q26;q22) translocations associated with myelogenous leukemias and encodes a DNA binding protein. From the AML1gene, three proteins, AML1a, AML1b and AML1c, are produced by alternative splicings. We previously showed that AML1 is potentially involved in myeloid cell differentiation. Here we analyzed the expression of AML1in myeloid cell lines. It was revealed that AML1b and AML1c are the major AML1 proteins in these cell lines and that prior to morphological and functional differentiation, their expressions increase in U937 cells when treated with all-transretinoic acid. These data suggest that the expression of AML1is associated with myeloid cell differentiation.