Arginine Methylation Provides Epigenetic Transcription Memory for Retinoid-Induced Differentiation in Myeloid Cells

Department of Biochemistry and Molecular Biology, Research Center for Molecular Medicine, University of Debrecen, Medical and Health Science Center, Nagyerdei krt. 98, Debrecen H-4012, Hungary.
Molecular and Cellular Biology (Impact Factor: 4.78). 08/2005; 25(13):5648-63. DOI: 10.1128/MCB.25.13.5648-5663.2005
Source: PubMed


Cellular differentiation is governed by changes in gene expression, but at the same time, a cell's identity needs to be maintained
through multiple cell divisions during maturation. In myeloid cell lines, retinoids induce gene expression and a well-characterized
two-step lineage-specific differentiation. To identify mechanisms that contribute to cellular transcriptional memory, we analyzed
the epigenetic changes taking place on regulatory regions of tissue transglutaminase, a gene whose expression is tightly linked
to retinoid-induced differentiation. Here we report that the induction of an intermediary or “primed” state of myeloid differentiation
is associated with increased H4 arginine 3 and decreased H3 lysine 4 methylation. These modifications occur before transcription
and appear to prime the chromatin for subsequent hormone-regulated transcription. Moreover, inhibition of methyltransferase
activity, preacetylation, or activation of the enzyme PAD4 attenuated retinoid-regulated gene expression, while overexpression
of PRMT1, a methyltransferase, enhanced retinoid responsiveness. Taken together, our results suggest that H4 arginine 3 methylation
is a bona fide positive epigenetic marker and regulator of transcriptional responsiveness as well as a signal integration
mechanism during cell differentiation and, as such, may provide epigenetic memory.

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    • "The EcoRI and XbaI restriction fragment containing the Prmt8N94-Prmt1 coding sequence was subcloned into pCS2+. Catalytic inactive Prmt8 with SGT to AAA mutations at the conserved AdoMet-binding site as Balint et al. [20] were introduced by site directed mutagenesis to produce the catalytic mutant. To observe embryos from the Tg(huC::eGFP) fish, images were taken by Leica DM2500 epifluorescence microscope with DFC490 CCD camera. "
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    ABSTRACT: Protein arginine methyltransferase (PRMT) 1 is the most conserved and widely distributed PRMT in eukaryotes. PRMT8 is a vertebrate-restricted paralogue of PRMT1 with an extra N-terminal sequence and brain-specific expression. We use zebrafish (Danio rerio) as a vertebrate model to study PRMT8 function and putative redundancy with PRMT1. The transcripts of zebrafish prmt8 were specifically expressed in adult zebrafish brain and ubiquitously expressed from zygotic to early segmentation stage before the neuronal development. Whole-mount in situ hybridization revealed ubiquitous prmt8 expression pattern during early embryonic stages, similar to that of prmt1. Knockdown of prmt8 with antisense morpholino oligonucleotide phenocopied prmt1-knockdown, with convergence/extension defects at gastrulation. Other abnormalities observed later include short body axis, curled tails, small and malformed brain and eyes. Catalytically inactive prmt8 failed to complement the morphants, indicating the importance of methyltransferase activity. Full-length prmt8 but not prmt1 cRNA can rescue the phenotypic changes. Nevertheless, cRNA encoding Prmt1 fused with the N-terminus of Prmt8 can rescue the prmt8 morphants. In contrast, N-terminus- deleted but not full-length prmt8 cRNA can rescue the prmt1 morphants as efficiently as prmt1 cRNA. Abnormal brain morphologies illustrated with brain markers and loss of fluorescent neurons in a transgenic fish upon prmt8 knockdown confirm the critical roles of prmt8 in neural development. In summery, our study is the first report showing the expression and function of prmt8 in early zebrafish embryogenesis. Our results indicate that prmt8 may play important roles non-overlapping with prmt1 in embryonic and neural development depending on its specific N-terminus.
    Full-text · Article · Mar 2013 · PLoS ONE
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    • "One of the known mechanisms through which PRMT1 activates transcription is by methylating the histone H4 on Arg3, which permits the subsequent acetylation of histones. This is demonstrated in the retinoic acid-induced expression of transglutaminase type 2 (TGM2) gene [34] and the DMSO-induced expression of β-globin gene [16]. The possibility that PRMT1-mediated up-regulation of transcription during erythroid differentiation involves histone H4 Arg3 methylation is not ruled out. "
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    ABSTRACT: Protein arginine methylation is emerging as a pivotal posttranslational modification involved in regulating various cellular processes; however, its role in erythropoiesis is still elusive. Erythropoiesis generates circulating red blood cells which are vital for body activity. Deficiency in erythroid differentiation causes anemia which compromises the quality of life. Despite extensive studies, the molecular events regulating erythropoiesis are not fully understood. This study showed that the increase in protein arginine methyltransferase 1 (PRMT1) levels, via transfection or protein transduction, significantly promoted erythroid differentiation in the bipotent human K562 cell line as well as in human primary hematopoietic progenitor CD34+ cells. PRMT1 expression enhanced the production of hemoglobin and the erythroid surface marker glycophorin A, and also up-regulated several key transcription factors, GATA1, NF-E2 and EKLF, which are critical for lineage-specific differentiation. The shRNA-mediated knockdown of PRMT1 suppressed erythroid differentiation. The methyltransferase activity-deficient PRMT1G80R mutant failed to stimulate differentiation, indicating the requirement of arginine methylation of target proteins. Our results further showed that a specific isoform of p38 MAPK, p38α, promoted erythroid differentiation, whereas p38β did not play a role. The stimulation of erythroid differentiation by PRMT1 was diminished in p38α- but not p38β-knockdown cells. PRMT1 appeared to act upstream of p38α, since expression of p38α still promoted erythroid differentiation in PRMT1-knockdown cells, and expression of PRMT1 enhanced the activation of p38 MAPK. Importantly, we showed for the first time that PRMT1 was associated with p38α in cells by co-immunoprecipitation and that PRMT1 directly methylated p38α in in vitro methylation assays. Taken together, our findings unveil a link between PRMT1 and p38α in regulating the erythroid differentiation program and provide evidence suggesting a novel regulatory mechanism for p38α through arginine methylation.
    Full-text · Article · Mar 2013 · PLoS ONE
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    • "The methyltransferase activity of PRMT1 is required for its repressive function in STAT1 signaling As PRMT1 possesses arginine methyltransferase activity toward histones and other nuclear proteins (Wang et al. 2001; Kwak et al. 2003; Barrero and Malik 2006) we studied in the following whether the catalytic activity of PRMT1 is required for its repressive function in STAT1- dependent transcription. Therefore, we established transient overexpression of wild-type PRMT1 (WT) and the catalytically inactive PRMT1 mutant XGX (Balint et al. 2005), which were equally well expressed (Fig. 4A). As expected IFNg-induced expression of CXCL9, CXCL10, and GBP1 was diminished in the presence of exogenous wild-type PRMT1 compared with control cells (Fig. 4B). "
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    ABSTRACT: To elucidate the function of the transcriptional coregulator PRMT1 (protein arginine methyltranferase 1) in interferon (IFN) signaling, we investigated the expression of STAT1 (signal transducer and activator of transcription) target genes in PRMT1-depleted cells. We show here that PRMT1 represses a subset of IFNgamma-inducible STAT1 target genes in a methyltransferase-dependent manner. These genes are also regulated by the STAT1 inhibitor PIAS1 (protein inhibitor of activated STAT1). PIAS1 is arginine methylated by PRMT1 in vitro as well as in vivo upon IFN treatment. Mutational and mass spectrometric analysis of PIAS1 identifies Arg 303 as the single methylation site. Using both methylation-deficient and methylation-mimicking mutants, we find that arginine methylation of PIAS1 is essential for the repressive function of PRMT1 in IFN-dependent transcription and for the recruitment of PIAS1 to STAT1 target gene promoters in the late phase of the IFN response. Methylation-dependent promoter recruitment of PIAS1 results in the release of STAT1 and coincides with the decline of STAT1-activated transcription. Accordingly, knockdown of PRMT1 or PIAS1 enhances the anti-proliferative effect of IFNgamma. Our findings identify PRMT1 as a novel and crucial negative regulator of STAT1 activation that controls PIAS1-mediated repression by arginine methylation.
    Preview · Article · Feb 2009 · Genes & development
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