Figure 5.

A stacked bar graph demonstrating the difference in αIIb and CMV promoter-targeted transgene expression to megakaryocyte and erythrocyte progeny of transduced CD34+ cells. Human CD34+ cells were transduced with MuLV-derived constructs, CMVnLacZ (bars 1 and 2) and −889nLacZ (bars 3 and 4) and then induced to expand and differentiate into a multilineage cell population. Histochemical staining was performed after 10 days of differentiation to determine the percent of the total cell population expressing β-gal for each promoter (hatched bars). The cells were simultaneously stained for β-gal activity and expression of the megakaryocyte-specific marker, αIIbβ3 (solid bars 1 and 3) or the erythrocyte-specific marker, GPA (solid bars 2 and 4) and scored to determine whether β-gal expression was selectively targeted to megakaryocytes. In a negative control, β-gal was not detected in untransduced cells. The results are from a single experiment that is representative of two experiments.