Figure 1.

v-Myb-ER fusion proteins block RA-induced morphological changes in 10.4 macrophage-like cells. (A) 10.4 cells were grown with solvent (EtOH) in the absence of RA and E₂, (B) treated with 1 μM RA for 18 h, and (C) treated with 1 μM RA plus 2 μM E₂ for 18 h. Light field photomicrographs of representative fields are shown. (D) RA antagonizes the induction of tom-1 expression by E₂ in cells expressing a v-Myb-ER fusion protein. Cells (10.4) were grown without ligands (lane 1) or treated for 18 h with 1 μM RA (lane 2) 2 μM E₂ (lane 3), or incubated simultaneously with both ligands (lane 4). Expression of tom-1 and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was analyzed by reverse transcription–PCR.