A Region Upstream of the Human δ-Globin Gene Shows a Stage-Specific Interaction with Globin Promoters in Erythroid Cell Lines

We previously showed that the 651-bp DNA fragment, located 3 kb upstream from the human gd-globin gene (fragment F5), is able to inhibit adult, not fetal, globin promoter in mouse erythroleukemia cell lines (MEL) expressing adult globin genes. Here we show in transient analysis that fragment F5 has a strong inhibitory effect on fetal gg-globin promoter in human erythroleukemia cell lines (HEL) expressing fetal globin genes. Since the gb-promoter constructs were poorly expressed in fetal cells, new plasmids containing an HPFH promoter (Gγ−175, T to C), which is strongly expressed in both fetal and adult cell lines, were made. Here we report that fragment F5 in HEL cells has a strong inhibitory effect on wild-type γ-promoter only; no effect was evident on γ−175-promoter in either MEL or HEL cell lines. Altogether these results show a stage-specific interaction between fragment F5 and globin promoters during development. We also report the presence of several bindings for erythroid GATA family factors by electrophoretic mobility shift assay, using nuclear extracts from erythroid cell lines.