Identification of a Novel Enhancer/Chromatin Opening Element Associated with High-Level ?-Globin Gene Expression.

ABSTRACT: The organization of the five ?-type globin genes on chromosome 11 reflects the timing of expression during erythroid cell development, with the embryonic ?-globin gene being located at the 5' end, followed by the two fetal ?-globin genes, and with the adult ?- and ?-globin genes being located at the 3' end. Here, we functionally characterized a DNase I-hypersensitive site (HS) located 4 kb upstream of the G?-globin gene (HBG-4kb HS). This site is occupied by transcription factors USF1, USF2, EGR1, MafK, and NF-E2 in the human erythroleukemia cell line K562 and exhibits histone modifications typical for enhancers. We generated a synthetic zinc finger (ZF) DNA-binding domain targeting the HBG-4kb HS (HBG-4kb ZF). The HBG-4kb ZF interacted with the target site in vitro and in the context of cells with a high affinity and specificity. Direct delivery of the HBG-4kb ZF to K562 and primary human erythroid cells caused a reduction in ?-globin gene expression which was associated with decreased binding of transcription factors and active histone marks at and downstream of the HS. The data demonstrate that the HBG-4kb HS is important for fetal globin production and suggest that it may act by opening chromatin in a directional manner.

SUBMITTER: Shen Y 

PROVIDER: S-EPMC6146835 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature