KLF1 stabilizes GATA-1 and TAL1 occupancy in the human β-globin locus.

KLF1 is an erythroid specific transcription factor that binds to regulatory regions of erythroid genes. Binding sites of KLF1 are often found near binding sites of GATA-1 and TAL1. In the β-globin locus, KLF1 is required for forming active chromatin structure, although its role is unclear. To explore the role of KLF1 in transcribing the human γ-globin genes, we stably reduced the expression of KLF1 in erythroid K562 cells, compromising its association in the β-globin locus. The γ-globin transcription was reduced with disappearance of active chromatin structure of the locus in the KLF1 knockdown cells. Interestingly, GATA-1 and TAL1 binding was reduced in the β-globin locus, even though their expressions were not affected by KLF1 knockdown. The KLF1-dependent GATA-1 and TAL1 binding was observed in the adult locus transcribing the β-globin gene and in several erythroid genes, where GATA-1 occupancy is independent from TAL1. These results indicate that KLF1 plays a role in facilitating and/or stabilizing GATA-1 and TAL1 occupancy in the erythroid genes, contributing to the generation of active chromatin structure such as histone acetylation and chromatin looping.