DNMT3A knockouts in human iPSCs prevent de novo DNA methylation and reveal growth advantage during hematopoietic differentiation

2021 ◽  
Author(s):  
Olivia Cypris ◽  
Julia Franzen ◽  
Joana Frobel ◽  
Philipp Glueck ◽  
Chao-Chung Kuo ◽  
...  

DNA methyltransferase 3A (DNMT3A) is a frequently mutated gene in many hematological malignancies, indicating that it may be essential for hematopoietic differentiation. Here, we addressed the functional relevance of DNMT3A for differentiation of human induced pluripotent stem cells (iPSCs) by knocking out exon 2, 19, or 23. Exon 19-/- and 23-/- lines revealed absence of almost the entire de novo DNA methylation during mesenchymal and hematopoietic differentiation. Yet, differentiation was only slightly reduced in exon 19-/- and increased in exon 23-/- lines, whereas there was no significant impact on gene expression in hematopoietic progenitors (iHPCs). Notably, DNMT3A-/- iHPCs recapitulate some DNA methylation differences of acute myeloid leukemia with DNMT3A mutations. Furthermore, multicolor genetic barcoding revealed competitive growth advantage of exon 23-/- iHPCs. Our results demonstrate that de novo DNA methylation during hematopoietic differentiation of iPSCs is almost entirely dependent on DNMT3A and exon 23-/- iHPCs even gained growth advantage.

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Shir Toubiana ◽  
Miriam Gagliardi ◽  
Mariarosaria Papa ◽  
Roberta Manco ◽  
Maty Tzukerman ◽  
...  

DNA methyltransferase 3B (DNMT3B) is the major DNMT that methylates mammalian genomes during early development. Mutations in human DNMT3B disrupt genome-wide DNA methylation patterns and result in ICF syndrome type 1 (ICF1). To study whether normal DNA methylation patterns may be restored in ICF1 cells, we corrected DNMT3B mutations in induced pluripotent stem cells from ICF1 patients. Focusing on repetitive regions, we show that in contrast to pericentromeric repeats, which reacquire normal methylation, the majority of subtelomeres acquire only partial DNA methylation and, accordingly, the ICF1 telomeric phenotype persists. Subtelomeres resistant to de novo methylation were characterized by abnormally high H3K4 trimethylation (H3K4me3), and short-term reduction of H3K4me3 by pharmacological intervention partially restored subtelomeric DNA methylation. These findings demonstrate that the abnormal epigenetic landscape established in ICF1 cells restricts the recruitment of DNMT3B, and suggest that rescue of epigenetic diseases with genome-wide disruptions will demand further manipulation beyond mutation correction.


2018 ◽  
Vol 1 (6) ◽  
pp. e201800153 ◽  
Author(s):  
Tanja Božić ◽  
Joana Frobel ◽  
Annamarija Raic ◽  
Fabio Ticconi ◽  
Chao-Chung Kuo ◽  
...  

De novo DNA methyltransferase 3A (DNMT3A) plays pivotal roles in hematopoietic differentiation. In this study, we followed the hypothesis that alternative splicing ofDNMT3Ahas characteristic epigenetic and functional sequels. SpecificDNMT3Atranscripts were either down-regulated or overexpressed in human hematopoietic stem and progenitor cells, and this resulted in complementary and transcript-specific DNA methylation and gene expression changes. Functional analysis indicated that, particularly, transcript 2 (coding for DNMT3A2) activates proliferation and induces loss of a primitive immunophenotype, whereas transcript 4 interferes with colony formation of the erythroid lineage. Notably, in acute myeloid leukemia expression of transcript 2 correlates with its in vitro DNA methylation and gene expression signatures and is associated with overall survival, indicating thatDNMT3Avariants also affect malignancies. Our results demonstrate that specificDNMT3Avariants have a distinct epigenetic and functional impact. Particularly, DNMT3A2 triggers hematopoietic differentiation and the corresponding signatures are reflected in acute myeloid leukemia.


2018 ◽  
Author(s):  
Tanja Božić ◽  
Joana Frobel ◽  
Annamarija Raic ◽  
Fabio Ticconi ◽  
Chao-Chung Kuo ◽  
...  

AbstractThede novoDNA methyltransferase 3A (DNMT3A) plays pivotal roles in hematopoietic differentiation. In this study, we followed the hypothesis that alternative splicing ofDNMT3Ahas characteristic epigenetic and functional sequels. SpecificDNMT3Atranscripts were either downregulated or overexpressed in human hematopoietic stem and progenitor cells and this resulted in complementary and transcript-specific DNA methylation and gene expression changes. Functional analysis indicated that particularly transcript 2 (coding for DNMT3A2) activates proliferation and induces loss of a primitive immunophenotype, whereas transcript 4 interferes with colony formation of the erythroid lineage. Notably, in acute myeloid leukemia (AML) expression of transcript 2 correlates with itsin vitroDNA methylation and gene expression signatures and is associated with overall survival, indicating thatDNMT3Avariants impact also on malignancies. Our results demonstrate that specificDNMT3Avariants have distinct epigenetic and functional impact. Particularly DNMT3A2 triggers hematopoietic differentiation and the corresponding signatures are reflected in AML.


Nature Plants ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 184-197
Author(s):  
Jianjun Jiang ◽  
Jie Liu ◽  
Dean Sanders ◽  
Shuiming Qian ◽  
Wendan Ren ◽  
...  

2020 ◽  
Vol 48 (7) ◽  
pp. 3949-3961 ◽  
Author(s):  
Chien-Chu Lin ◽  
Yi-Ping Chen ◽  
Wei-Zen Yang ◽  
James C K Shen ◽  
Hanna S Yuan

Abstract DNA methyltransferases are primary enzymes for cytosine methylation at CpG sites of epigenetic gene regulation in mammals. De novo methyltransferases DNMT3A and DNMT3B create DNA methylation patterns during development, but how they differentially implement genomic DNA methylation patterns is poorly understood. Here, we report crystal structures of the catalytic domain of human DNMT3B–3L complex, noncovalently bound with and without DNA of different sequences. Human DNMT3B uses two flexible loops to enclose DNA and employs its catalytic loop to flip out the cytosine base. As opposed to DNMT3A, DNMT3B specifically recognizes DNA with CpGpG sites via residues Asn779 and Lys777 in its more stable and well-ordered target recognition domain loop to facilitate processive methylation of tandemly repeated CpG sites. We also identify a proton wire water channel for the final deprotonation step, revealing the complete working mechanism for cytosine methylation by DNMT3B and providing the structural basis for DNMT3B mutation-induced hypomethylation in immunodeficiency, centromere instability and facial anomalies syndrome.


2021 ◽  
Author(s):  
Masaki Shirai ◽  
Takuya Nara ◽  
Haruko Takahashi ◽  
Kazuya Takayama ◽  
Yuan Chen ◽  
...  

CpG methylation in genomic DNA is well known as a repressive epigenetic marker in eukaryotic transcription, and DNA methylation of the promoter regions is correlated with silencing of gene expression. In contrast to the promoter regions, the function of DNA methylation during transcription termination remains to be elucidated. A recent study has revealed that mouse DNA methyltransferase 3a (Dnmt3a) mainly functions in de novo methylation in the promoter and gene body regions (including transcription termination sites (TTSs)) during development. To investigate the relationship between DNA methylation overlapping the TTSs and transcription termination, we employed two strategies: informatic analysis using already deposited datasets of Dnmt3a-/- mouse cells and the zebrafish model system. Bioinformatic analysis using methylome and transcriptome data showed that hypomethylated differentially methylated regions overlapping the TTSs were associated with increased read counts and chimeric transcripts downstream of TTSs in Dnmt3a-/- Agouti-related protein neurons, but not in Dnmt3a-/- ES cells and MEFs. We experimentally detected increased read-through and chimeric transcripts downstream of hypomethylated TTSs in zebrafish maternal-zygotic dnmt3aa-/- mutants. This study is the first to identify transcription termination defects in DNA hypomethylated TTSs in Dnmt3a-/- vertebrates.


Life ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1325
Author(s):  
Fenfen Li ◽  
Xin Cui ◽  
Jia Jing ◽  
Shirong Wang ◽  
Huidong Shi ◽  
...  

Obesity results from a chronic energy imbalance due to energy intake exceeding energy expenditure. Activation of brown fat thermogenesis has been shown to combat obesity. Epigenetic regulation, including DNA methylation, has emerged as a key regulator of brown fat thermogenic function. Here we aimed to study the role of Dnmt3b, a DNA methyltransferase involved in de novo DNA methylation, in the regulation of brown fat thermogenesis and obesity. We found that the specific deletion of Dnmt3b in brown fat promotes the thermogenic and mitochondrial program in brown fat, enhances energy expenditure, and decreases adiposity in female mice fed a regular chow diet. With a lean phenotype, the female knockout mice also exhibit increased insulin sensitivity. In addition, Dnmt3b deficiency in brown fat also prevents diet-induced obesity and insulin resistance in female mice. Interestingly, our RNA-seq analysis revealed an upregulation of the PI3K-Akt pathway in the brown fat of female Dnmt3b knockout mice. However, male Dnmt3b knockout mice have no change in their body weight, suggesting the existence of sexual dimorphism in the brown fat Dnmt3b knockout model. Our data demonstrate that Dnmt3b plays an important role in the regulation of brown fat function, energy metabolism and obesity in female mice.


eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Jered M Wendte ◽  
Yinwen Zhang ◽  
Lexiang Ji ◽  
Xiuling Shi ◽  
Rashmi R Hazarika ◽  
...  

In many plant species, a subset of transcribed genes are characterized by strictly CG-context DNA methylation, referred to as gene body methylation (gbM). The mechanisms that establish gbM are unclear, yet flowering plant species naturally without gbM lack the DNA methyltransferase, CMT3, which maintains CHG (H = A, C, or T) and not CG methylation at constitutive heterochromatin. Here, we identify the mechanistic basis for gbM establishment by expressing CMT3 in a species naturally lacking CMT3. CMT3 expression reconstituted gbM through a progression of de novo CHG methylation on expressed genes, followed by the accumulation of CG methylation that could be inherited even following loss of the CMT3 transgene. Thus, gbM likely originates from the simultaneous targeting of loci by pathways that promote euchromatin and heterochromatin, which primes genes for the formation of stably inherited epimutations in the form of CG DNA methylation.


1998 ◽  
Vol 18 (9) ◽  
pp. 5166-5177 ◽  
Author(s):  
Judy A. Mikovits ◽  
Howard A. Young ◽  
Paula Vertino ◽  
Jean-Pierre J. Issa ◽  
Paula M. Pitha ◽  
...  

ABSTRACT The immune response to pathogens is regulated by a delicate balance of cytokines. The dysregulation of cytokine gene expression, including interleukin-12, tumor necrosis factor alpha, and gamma interferon (IFN-γ), following human retrovirus infection is well documented. One process by which such gene expression may be modulated is altered DNA methylation. In subsets of T-helper cells, the expression of IFN-γ, a cytokine important to the immune response to viral infection, is regulated in part by DNA methylation such that mRNA expression inversely correlates with the methylation status of the promoter. Of the many possible genes whose methylation status could be affected by viral infection, we examined the IFN-γ gene as a candidate. We show here that acute infection of cells with human immunodeficiency virus type 1 (HIV-1) results in (i) increased DNA methyltransferase expression and activity, (ii) an overall increase in methylation of DNA in infected cells, and (iii) the de novo methylation of a CpG dinucleotide in the IFN-γ gene promoter, resulting in the subsequent downregulation of expression of this cytokine. The introduction of an antisense methyltransferase construct into lymphoid cells resulted in markedly decreased methyltransferase expression, hypomethylation throughout the IFN-γ gene, and increased IFN-γ production, demonstrating a direct link between methyltransferase and IFN-γ gene expression. The ability of increased DNA methyltransferase activity to downregulate the expression of genes like the IFN-γ gene may be one of the mechanisms for dysfunction of T cells in HIV-1-infected individuals.


2009 ◽  
Vol 21 (9) ◽  
pp. 43
Author(s):  
Y. Li ◽  
H. D. Morgan ◽  
L. Ganeshan ◽  
C. O'Neill

In an accompanying abstract we show for the first time that global demethylation of both paternally- and maternally-derived genomes occurs prior to syngamy. It is commonly considered that new methylation of the genome does not commence until late in the preimplantation stage. Yet embryos during cleavage stage are known to show DNA methylation. This creates a paradox, if global demethylation occurs by the time of syngamy yet remethylation does not occur until the blastocysts stage, how can cleavage stage embryos possess methylated DNA. We examined this paradox. We examined DNA methylation in 2-cell embryos by confocal microscopy of anti-methylcytosine immunofluorescence and propidium iodide co-staining of whole mounts. We confirmed that DNA in late zygotes was substantially demethylated in both the male and female pronuclei. By the 2-cell stage, embryos collected direct from the oviduct showed high levels of cytosine methylation. We assessed whether this accumulation of cytosine methylation during the early 2-cell stage was a consequence of DNA methyltransferase (DNMT) activity. This was achieved by treating late stage zygotes with the DNMT inhibitor RG108 (5 μM) for the period of development spanning pronuclear stage 5 to early 2-cell stage. The embryos that developed in the presence of the DNA methyltransferase inhibitor showed significantly less methylcytosine staining than the embryos in the untreated culture conditions (P<0.001). Treatment of embryos during this period with RG108 significantly reduced their capacity to develop to normal blastocysts, indicating that this early DNA re-methylation reaction was important for the normal development of the embryo. Our results show for the first time that de novo methylation of the genome occurs as early as the 2-cell stage of development and that this is mediated by a RG108-sensitive DNMT activity. The results substantially change our understanding of epigenetic reprogramming in the early embryo.


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