Transcriptional silencing of fetal hemoglobin expression by NonO.
Nucleic Acids Res
; 49(17): 9711-9723, 2021 09 27.
Article
in En
| MEDLINE
| ID: mdl-34379783
ABSTRACT
Human fetal globin (γ-globin) genes are developmentally silenced after birth, and reactivation of γ-globin expression in adulthood ameliorates symptoms of hemoglobin disorders, such as sickle cell disease (SCD) and ß-thalassemia. However, the mechanisms by which γ-globin expression is precisely regulated are still incompletely understood. Here, we found that NonO (non-POU domain-containing octamer-binding protein) interacted directly with SOX6, and repressed the expression of γ-globin gene in human erythroid cells. We showed that NonO bound to the octamer binding motif, ATGCAAAT, of the γ-globin proximal promoter, resulting in inhibition of γ-globin transcription. Depletion of NonO resulted in significant activation of γ-globin expression in K562, HUDEP-2, and primary human erythroid progenitor cells. To confirm the role of NonO in vivo, we further generated a conditional knockout of NonO by using IFN-inducible Mx1-Cre transgenic mice. We found that induced NonO deletion reactivated murine embryonic globin and human γ-globin gene expression in adult ß-YAC mice, suggesting a conserved role for NonO during mammalian evolution. Thus, our data indicate that NonO acts as a novel transcriptional repressor of γ-globin gene expression through direct promoter binding, and is essential for γ-globin gene silencing.
Full text:
1
Database:
MEDLINE
Main subject:
Fetal Hemoglobin
/
RNA-Binding Proteins
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Gene Silencing
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DNA-Binding Proteins
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Gamma-Globins
Limits:
Animals
/
Humans
Language:
En
Year:
2021
Type:
Article