Fig. 7. Summary of the chromatin structure at the boundaries of the chicken β-globin locus in erythroid cells. A schematic view of the region extending from the chicken β-globin locus is shown. CTCF binds to both the 5′ and 3′ chromatin boundaries (Bell et al., 1999; this study), and may be involved in shielding the β-globin locus from regulatory effects from neighboring genes: the upstream folate receptor gene (Prioleau et al., 1999) and the downstream odorant receptor gene (Bulger et al., 1999; this study), respectively.