PML/RARα and PLZF/RARα arrest ECoM-G differentiation in the absence of estrogen and endow the cells with RA sensitivity.

Derivatives of one ECoM-G clone were established by retroviral infection with constructs encoding PML/RARα and PLZF/RARα followed by selection of immortalized cells in the absence of estrogen. Parental ECoM-G cells (maintained in estrogen) as well as PML/RARα-immortalized and PLZF/RARα-immortalized cells (in the absence of estrogen) were treated for 4 days with 10 μM atRA. Table 1presents data from Wright-Giemsa stains of cytocentrifuge preparations, as well as the percent of mitotic progenitors and mature granulocytes compiled from a minimum of 200 cells.