Reduced expression of γ-globin in K562 cells expressing the ZF@Gγ-4KbDHS. K562 cells were transfected with a plasmid expressing the ZF@Gγ-4KbDHS or with an empty vector. The K562 cells (pool) were subjected to Western blotting (A) and to Chromatin Immunoprecipitation (ChIP) using antibodies specific for the FLAG-tag, which is linked to the ZF@Gγ-4KbDHS, or negative control antibodies IgG (B). Single clonal K562 cells were subjected to Western blotting using antibodies specific for the ZF-DBD backbone (αZF) or for CTCF or GATA-1 as indicated (C). The single cell clone expressing the ZF@Gγ-4KbDHS was subjected to expression analysis by RT-qPCR using primers specific for γ-globin or GATA-1 as indicated (D).