Experimental strategy and protein expression in primary hematopoietic progenitors.(A) Scheme of the experimental approach used to study the effect of RAR-fusion genes on the proliferation and myeloid differentiation of the target cells and to evaluate the responsiveness of the transformed cells to retinoic acid. (B) Western blot analysis of cells transduced with the different vectors after 8 days of culture in methylcellulose (20 μg of protein was loaded per lane). When indicated, the cells were grown in the presence of RA (1 μmol/L). Arrows point to exogenously expressed proteins detected with the specific antihuman retinoid receptor antibodies indicated above each panel.