Transcription factor EKLF (KLF1) recruitment of the histone chaperone HIRA is essential for ß-globin gene expression.

The binding of chromatin-associated proteins and incorporation of histone variants correlates with alterations in gene expression. These changes have been particularly well analyzed at the mammalian ß-globin locus, where transcription factors such as erythroid Krüppel-like factor (EKLF), which is also known as Krüppel-like factor 1 (KLF1), play a coordinating role in establishing the proper chromatin structure and inducing high-level expression of adult ß-globin. We had previously shown that EKLF preferentially interacts with histone H3 and that the H3.3 variant is differentially recruited to the ß-globin promoter. We now find that a novel interaction between EKLF and the histone cell cycle regulation defective homolog A (HIRA) histone chaperone accounts for these effects. HIRA is not only critical for ß-globin expression but is also required for activation of the erythropoietic regulators EKLF and GATA binding protein 1 (GATA1). Our results provide a mechanism by which transcription factor-directed recruitment of a generally expressed histone chaperone can lead to tissue-restricted changes in chromatin components, structure, and transcription at specific genomic sites during differentiation.