Histone Methyltransferase Setd8 Represses Gata2 Expression and Regulates Erythroid Maturation

Abstract

Setd8 is the sole histone methyltransferase in mammals capable of monomethylating histone H4 lysine 20 (H4K20me1). Setd8 is expressed at significantly higher levels in erythroid cells than any other cell or tissue type, suggesting that Setd8 has an erythroidcell-specific function. To test this hypothesis, stable Setd8 knockdown was established in extensively self-renewing erythroblasts (ESREs), a well-characterized, nontransformed model of erythroid maturation. Knockdown of Setd8 resulted in impaired erythroid maturation characterized by a delay in hemoglobin accumulation, larger mean cell area, persistent ckit expression, incomplete nuclear condensation, and lower rates of enucleation. Setd8 knockdown did not alter ESRE proliferation or viability or result in accumulation of DNA damage. Global gene expression analyses following Setd8 knockdown demonstrated that in erythroid cells, Setd8 functions primarily as a repressor. Most notably, Gata2 expression was significantly higher in knockdown cells than in control cells and Gata2 knockdown rescued some of the maturation impairments associated with Setd8 disruption. Setd8 occupies critical regulatory elements in the Gata2 locus, and knockdown of Setd8 resulted in loss of H4K20me1 and gain of H4 acetylation at the Gata2 1S promoter. These results suggest that Setd8 is an important regulator of erythroid maturation that works in part through repression of Gata2 expression.

Epigenetic Determinants of Erythropoiesis: Role of the Histone Methyltransferase SetD8 in Promoting Erythroid Cell Maturation and Survival

“…Given the massive chromatin and nuclear reconfiguration associated with erythroid maturation (77,78), the erythroid system offers unique potential to elucidate how a histonemodifying enzyme orchestrates and/or negotiates complex nuclear transactions in a specialized, but critical, cell type from a multicellular organism. See the companion article by Malik et al (79).…”

Epigenetic DNA Methylation Profiling with MSRE: A Quantitative NGS Approach Using a Parkinson's Disease Test Case

“…First, KMT5A or SETx, is a protein N-lysine methyltransferase that monomethylates both histones and non-histone proteins. Histone 4 (H4K20) is a target and is methylated during mitosis and represents a specific tag for epigenetic transcriptional repression (Kalakonda et al, 2008; West et al, 2010; Malik et al, 2015). Second, HTT, is Huntington Disease Protein or Huntingtin, for which there are well established neurodegenerative actions (Gusella et al, 2014; Kaliszewski et al, 2015; Kumar et al, 2015; Labadorf and Myers, 2015).…”

Orchestration of late events in erythropoiesis by KLF1/EKLF

“…In particular, Setd8, a mono-methyltransferase that modifies histone H4K20 [56], plays an important role by inhibiting erythroid maturation [57*], resulting in incomplete nuclear condensation and lower enucleation levels [58*]. Its expression is higher in erythroid precursors than other cell types, and knockdown studies show that part of its function involves repressing Gata2 and thus promoting erythroid maturation [57*,58*]. Its effects on nuclear condensation and extrusion may follow from its established cell cycle-dependent variation in levels [59–61], linking condensation to the limited number of cycles prior to cell cycle exit.…”