Zhang Z1Costa FC2Tan EP1Bushue N1DiTacchio L3Costello CE4McComb ME4Whelan SA4Peterson KR5Slawson C6. 2016. J. Biol Chem 291:15628-40.  doi: 10.1074/jbc.M116.721928. Epub 2016 May 26.  
1From the Department of Biochemistry and Molecular Biology.
2IntelligeneDx Cancer Genomics, Olathe, Kansas 66061.
3Pharmacology, Toxicology and Therapeutics.
4Department of Biochemistry and Center for Biomedical Mass Spectrometry, Boston University School of Medicine, Boston, Massachusetts 02118, and.
5From the Department of Biochemistry and Molecular Biology, Anatomy and Cell Biology, and Cancer Center, Institute for Reproductive Health and Regenerative Medicine, and kpeterson@kumc.edu.
6From the Department of Biochemistry and Molecular Biology, Cancer Center, Institute for Reproductive Health and Regenerative Medicine, and Alzheimer's Disease Center, University of Kansas Medical Center, Kansas City, Kansas 66160, cslawson@kumc.edu.


One mode of γ-globin gene silencing involves a GATA-1·FOG-1·Mi2β repressor complex that binds to the -566 GATA site relative to the (A)γ-globin gene cap site. However, the mechanism of how this repressor complex is assembled at the -566 GATA site is unknown. In this study, we demonstrate that the O-linked N-acetylglucosamine (O-GlcNAc) processing enzymes, O-GlcNAc-transferase (OGT) and O-GlcNAcase (OGA), interact with the (A)γ-globin promoter at the -566 GATA repressor site; however, mutation of the GATA site to GAGA significantly reduces OGT and OGA promoter interactions in β-globin locus yeast artificial chromosome (β-YAC) bone marrow cells. When WT β-YAC bone marrow cells are treated with the OGA inhibitor Thiamet-G, the occupancy of OGT, OGA, and Mi2β at the (A)γ-globin promoter is increased. In addition, OGT and Mi2β recruitment is increased at the (A)γ-globin promoter when γ-globin becomes repressed in postconception day E18 human β-YAC transgenic mouse fetal liver. Furthermore, we show that Mi2β is modified with O-GlcNAc, and both OGT and OGA interact with Mi2β, GATA-1, and FOG-1. Taken together, our data suggest that O-GlcNAcylation is a novel mechanism of γ-globin gene regulation mediated by modulating the assembly of the GATA-1·FOG-1·Mi2β repressor complex at the -566 GATA motif within the promoter.




CHD4; FOG; GATA transcription factor; Globin; O-GlcNAc-transferase; O-GlcNAcase; O-GlcNAcylation; O-linked N-acetylglucosamine (O-GlcNAc); post-translational modification (PTM); transcription

 [Available on 2017-07-22]
[PubMed - in process]