Acetylation of C/EBPα inhibits its granulopoietic function.

Deepak Bararia,Akihiko Numata,Debleena Ray,Elena Levantini,Sheena Wee,Hui Si Kwok,Sebastian Tschuri,Robert S Welner,Alexander K Ebralidze,Jayantha Gunaratne,Menyhárt B Sárosi,Daniel G Tenen,Henry Yang,Oliver Weigert

doi:10.1038/ncomms10968

Abstract

CCAAT/enhancer-binding protein alpha (C/EBPα) is an essential transcription factor for myeloid lineage commitment. Here we demonstrate that acetylation of C/EBPα at lysine residues K298 and K302, mediated at least in part by general control non-derepressible 5 (GCN5), impairs C/EBPα DNA-binding ability and modulates C/EBPα transcriptional activity. Acetylated C/EBPα is enriched in human myeloid leukaemia cell lines and acute myeloid leukaemia (AML) samples, and downregulated upon granulocyte-colony stimulating factor (G-CSF)- mediated granulocytic differentiation of 32Dcl3 cells. C/EBPα mutants that mimic acetylation failed to induce granulocytic differentiation in C/EBPα-dependent assays, in both cell lines and in primary hematopoietic cells. Our data uncover GCN5 as a negative regulator of C/EBPα and demonstrate the importance of C/EBPα acetylation in myeloid differentiation.

Highlights

CCAAT/enhancer-binding protein alpha (C/EBPa) is an essential transcription factor for myeloid lineage commitment
We identify the ability of KAT general control non-derepressible 5 (GCN5) to interact and acetylate C/EBPa on at least lysine K298 and K302 in the basic DNA-binding domain (DBD), which results in impaired DNA-binding activity
Given C/EBPa expression normally triggers differentiation of immature myeloblasts into mature granulocytes, we investigated why some leukaemic cell lines remain undifferentiated despite high levels of expression of non-mutated C/EBPa

Summary

Introduction

CCAAT/enhancer-binding protein alpha (C/EBPa) is an essential transcription factor for myeloid lineage commitment. We demonstrate that acetylation of C/EBPa at lysine residues K298 and K302, mediated at least in part by general control non-derepressible 5 (GCN5), impairs C/EBPa DNA-binding ability and modulates C/EBPa transcriptional activity. Acetylated C/EBPa is enriched in human myeloid leukaemia cell lines and acute myeloid leukaemia (AML) samples, and downregulated upon granulocyte-colony stimulating factor (G-CSF)- mediated granulocytic differentiation of 32Dcl[3] cells. CCAAT/enhancer-binding protein alpha (C/EBPa) is one of the transcription factors that is crucial for both myeloid differentiation and maintenance of quiescence in adult HSCs. The role of C/EBPa in granulopoiesis is demonstrated through Mx1-Cre-driven conditional disruption of C/EBPa in adult mice, resulting in a differentiation block during the transition from common myeloid progenitors to granulocyte monocyte progenitors and increased HSC self-renewal[1,2]. C/EBPa acetylation is detectable in myeloid cell lines, primary leukaemic samples and drops dramatically during granulocytic differentiation of 32Dcl[3] cells on granulocyte-colony stimulating factor (G-CSF) treatment. Our study is the first to provide an understanding of how C/EBPa activity is regulated by KAT at the post-translational level

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Conclusion