Control of differentiation in a self-renewing mammalian tissue by the histone demethylase JMJD3

Abstract

The recent discovery of H3K27me3 demethylases suggests that H3K27me3 may dynamically regulate gene expression, but this potential role in mammalian tissue homeostasis remains uncharacterized. In the epidermis, a tissue that balances stem cell self-renewal with differentiation, H3K27me3, occupies the promoters of many differentiation genes. During calcium-induced differentiation, H3K27me3 was erased at these promoters in concert with loss of PcG protein occupancy and increased binding by the H3K27me3 demethylase, JMJD3. Within epidermal tissue, JMJD3 depletion blocked differentiation, while active JMJD3 dominantly induced it. These results indicate that epigenetic derepression by JMJD3 controls mammalian epidermal differentiation.Supplemental material is available at http://www.genesdev.org.Received March 12, 2008; revised version accepted May 22, 2008. Post-translational modifications of core histone octamer proteins, in the form of phosphorylation, acetylation, ubiquitination, and methylation, have been increasingly appreciated as powerful regulators of gene expression. In Drosophila and mammals, the histone 3 Lys 27 trimethylation mark (H3K27me3) is associated with repression of gene transcription (Lund and van Lohuizen 2004;Barski et al. 2007). Polycomb group proteins (PcG) and their antagonists, the histone demethylases, are epigenetic regulators that control gene expression by modifying the methylation status of H3K27 (Grimaud et al. 2006;Swigut and Wysocka 2007). The PcG protein, Enhancer of Zest Homolog 2 (EZH2), is a histone methyltransferase that can trimethylate H3K27. Two other PcG proteins, Embryonic Ectoderm Development (EED) and Suppressor of Zeste 12 homolog (SUZ12), are necessary for EZH2 to function properly (Pasini et al. 2004). Genome-wide mapping of H3K27me3 marks and PcG target sites in embryonic stem cells has recently suggested a major role for PcG proteins in maintaining H3K27me3 to allow for repression of the differentiated state and promotion of embryonic stem cell self-renewal, with significant enrichment of these proteins on genes encoding homeodomain proteins and other putative differentiation factors Lee et al. 2006). The mechanism reversing such potential repressive influences on differentiation gene expression by H3K27me3 and other histone modifications in somatic tissue is not fully characterized.Among potential mediators of differentiation gene derepression are newly characterized Jumanji C (JmjC) domain-containing proteins, UTX and JMJD3, which are enzymes capable of demethylating promoters marked by H3K27me3. Recently, the H3K27 demethylase activity of UTX and JMJD3 has been shown to act at HOX gene promoters to derepress HOX gene transcription (Agger et al. 2007;Lan et al. 2007;Lee et al. 2007). These histone demethylases were demonstrated in mammalian cells and in live zebrafish to antagonize PcG gene silencing by modifying chromatin to permit gene transcription. During inflammation, bacterial products and cytokines induce JMJD3, which then removes H3K27me3 marks to dere...

Epigenetic regulation of aging stem cells

“…As a primary example, the H3K27me3 histone lysine demethylase JMJD3 functions to mediate stem cell differentiation potential. In undifferentiated human keratinocytes, a form of unipotent adult stem cell, JMJD3 is required to remove repressive H3K27me3 marks at pro-differentiation genes (Sen et al, 2008). Consistently, overexpression of JMJD3 drives premature keratinocyte differentiation (Sen et al, 2008).…”

“…In undifferentiated human keratinocytes, a form of unipotent adult stem cell, JMJD3 is required to remove repressive H3K27me3 marks at pro-differentiation genes (Sen et al, 2008). Consistently, overexpression of JMJD3 drives premature keratinocyte differentiation (Sen et al, 2008). Similarly, in the developing nervous system of mice, JMJD3 promotes differentiation upon induction of retinoic acid signaling, and its suppression is required for the maintenance of an uncommitted stem cell state (Jepsen et al, 2007).…”

Enhancer-targeted genome editing selectively blocks innate resistance to oncokinase inhibition

“…Lysis with a modified RIPA buffer (1% NP40/Igepal, 0.5% Sodium Deoxycholate, 0.1% SDS, 100 uM EDTA in PBS), nuclei were isolated and overnight pulldown was performed with an antibody to MITF (Sigma HPA003259), H3K27ac (Abcam ab4729), H3K4me1 (Abcam ab8895), or Rabbit IgG control (Abcam ab37415). Staph A cells were used for pulldown and washes were performed as described previously (Sen et al 2008). Isolated DNA was subject to qPCR with primers in Supplemental Table 6.…”

“…Cells were trypsinized, washed, and cross-linked as described previously (Sen et al 2008). Lysis with a modified RIPA buffer (1% NP40/Igepal, 0.5% Sodium Deoxycholate, 0.1% SDS, 100 uM EDTA in PBS), nuclei were isolated and overnight pulldown was performed with an antibody to MITF (Sigma HPA003259), H3K27ac (Abcam ab4729), H3K4me1 (Abcam ab8895), or Rabbit IgG control (Abcam ab37415).…”

Development and Homeostasis of the Skin Epidermis

“…Double conditional knockout mice for HDAC1/2 have thin, smooth skin and failure for limb-digit separation and eyelid fusion (LeBoeuf et al 2010). Small interfering RNA-mediated deletion of JMJD3, an H3K27me3 demethylase in organotypic human epidermal cultures, prevented epidermal differentiation, whereas conversely, JMJD3 overexpression led to premature differentiation (Sen et al 2008). Whereas conditional deletion in the epidermis of the polycomb complex protein Ezh2 alone leads to rather mild phenotype (Ezhkova et al 2009), conditional deletion of both EZH1/2 differentially affects HF and IFE.…”