Mammalian DNMTs in the male germ line DNA of Drosophila

2008 ◽  
Vol 86 (5) ◽  
pp. 380-385 ◽  
Author(s):  
Alexandra Weyrich ◽  
Xiaojing Tang ◽  
Guoliang Xu ◽  
André Schrattenholz ◽  
Christian Hunzinger ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Drosophila Melanogaster ◽  
Functional Role ◽  
De Novo ◽  
Germ Line ◽  
Dna Methyltransferases ◽  
Male Germ Line ◽  
Nuclear Regions ◽  
Functional Relevance

It is controversial whether DNA methylation plays a functional role in Drosophila . We have studied testis DNA of Drosophila melanogaster Meigen, 1830 with antisera against 5-methylcytosine (5mC) and found no evidence for the presence of significant amounts of 5mC. Reactions occur only with 1 of 3 5mC antisera, but they are restricted to nuclear regions without detectable amounts of DNA. The antisera apparently cross-react with other nuclear components. If the murine de novo DNA methyltransferases, DNMT3A and DNMT3B, are expressed under the control of the spermatocyte-specific β2-tubulin promoter in testes, DNA methylation is not increased and no effects on the fertility of the fly are seen. DNA methylation has, therefore, no functional relevance in the male germ line of Drosophila.

scholarly journals De Novo DNA Methylation in the Male Germ Line Occurs by Default but Is Excluded at Sites of H3K4 Methylation

Cell Reports ◽  
2013 ◽  
Vol 4 (1) ◽  
pp. 205-219 ◽  
Author(s):  
Purnima Singh ◽  
Arthur X. Li ◽  
Diana A. Tran ◽  
Nathan Oates ◽  
Eun-Rim Kang ◽  
...  
Keyword(s):  
Dna Methylation ◽  
De Novo ◽  
Germ Line ◽  
H3k4 Methylation ◽  
Male Germ Line

scholarly journals Mechanisms of DNA Methyltransferase Recruitment in Mammals

Genes ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 617 ◽  
Author(s):  
Marthe Laisné ◽  
Nikhil Gupta ◽  
Olivier Kirsh ◽  
Sriharsa Pradhan ◽  
Pierre-Antoine Defossez
Keyword(s):  
Dna Methylation ◽  
Transcription Factors ◽  
Functional Role ◽  
Dna Methyltransferase ◽  
De Novo ◽  
Dna Methyltransferases ◽  
Future Research ◽  
Epigenetic Mark ◽  
Epigenetic Events ◽  
Chromatin Modifiers

DNA methylation is an essential epigenetic mark in mammals. The proper distribution of this mark depends on accurate deposition and maintenance mechanisms, and underpins its functional role. This, in turn, depends on the precise recruitment and activation of de novo and maintenance DNA methyltransferases (DNMTs). In this review, we discuss mechanisms of recruitment of DNMTs by transcription factors and chromatin modifiers—and by RNA—and place these mechanisms in the context of biologically meaningful epigenetic events. We present hypotheses and speculations for future research, and underline the fundamental and practical benefits of better understanding the mechanisms that govern the recruitment of DNMTs.

scholarly journals Dnmt3aa But Not Dnmt3ab Is Required for Maintenance of Gametogenesis in Nile Tilapia

2021 ◽  
Author(s):  
Feilong Wang ◽  
Zuliang Qin ◽  
Zhiqiang Li ◽  
Shuangyi Yang ◽  
Tian Gao ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Granulosa Cells ◽  
Nile Tilapia ◽  
De Novo ◽  
Germ Line ◽  
Sperm Quality ◽  
Gonadosomatic Index ◽  
Expression Patterns ◽  
Dna Methyltransferases ◽  
Homozygous Mutation

Abstract Background: Dnmt3a , a de novo methylatransferase, is essential for both male and female germ line DNA methylation. Only one Dnmt3a is identified in mammals, and homozygous mutation of Dnmt3a is lethal, while two Dnmt3a , dnmt3aa and dnmt3ab , are identified in teleosts due to the third round of genome duplication, and homozygous mutation of dnmt3aa and dnmt3ab is viable in zebrafish. Dnmt3aa and dnmt3ab were demonstrated to have essential and non-overlapped functions on modulating behavioral control, however, their function in gonadal development is unclear in fish. Results: In this study, the expression patterns of dnmt3aa and dnmt3ab in developing gonads of Nile tilapia was analyzed by quantitative real time PCR and fluorescence in situ hybridization. Both dnmt3aa and dnmt3ab displayed sexually dimorphic expression in developing gonads. Dnmt3aa was widely expressed in gonadal germ cells and somatic cells, highly expressed in oogonia, phase I and II oocytes and granulosa cells in ovaries and spermatogonia and spermatocytes in testes, while dnmt3ab was mainly expressed in ovarian granulosa cells and testicular spermatocytes. Mutation of dnmt3aa and dnmt3ab was achieved by CRISPR/Cas9 in tilapia. Lower GSI (Gonadosomatic index), increased apoptosis of oocytes and spermatocytes and significantly reduced sperm quality were observed in dnmt3aa −/− mutants, while no obvious phenotype was observed in dnmt3ab −/− mutants. Consistently, the expression of apoptotic genes was significantly increased in dnmt3aa −/− mutants. In addition, dnmt3aa and dnmt3ab were found to have certain compensatory effects in the gonads. The global DNA methylation level in ovaries and testes of dnmt3aa −/− mutants was decreased significantly, compared with that of dnmt3ab −/− mutants and WT. Conclusions: Taken together, our results suggest that dnmt3aa , not dnmt3ab , plays important roles in maintaining gametogenesis in teleost. Our results enrich the understanding of the function of DNA methyltransferases in gonads of non-mammalian vertebrates.

scholarly journals Interplay between Histone and DNA Methylation Seen through Comparative Methylomes in Rare Mendelian Disorders

2021 ◽  
Vol 22 (7) ◽  
pp. 3735
Author(s):  
Guillaume Velasco ◽  
Damien Ulveling ◽  
Sophie Rondeau ◽  
Pauline Marzin ◽  
Motoko Unoki ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Catalytic Domain ◽  
De Novo ◽  
Mutation Screening ◽  
Histone H3 ◽  
Regulatory Elements ◽  
Germline Mutations ◽  
Dna Methyltransferases ◽  
Mendelian Disorders ◽  
Epigenetic Machinery

DNA methylation (DNAme) profiling is used to establish specific biomarkers to improve the diagnosis of patients with inherited neurodevelopmental disorders and to guide mutation screening. In the specific case of mendelian disorders of the epigenetic machinery, it also provides the basis to infer mechanistic aspects with regard to DNAme determinants and interplay between histone and DNAme that apply to humans. Here, we present comparative methylomes from patients with mutations in the de novo DNA methyltransferases DNMT3A and DNMT3B, in their catalytic domain or their N-terminal parts involved in reading histone methylation, or in histone H3 lysine (K) methylases NSD1 or SETD2 (H3 K36) or KMT2D/MLL2 (H3 K4). We provide disease-specific DNAme signatures and document the distinct consequences of mutations in enzymes with very similar or intertwined functions, including at repeated sequences and imprinted loci. We found that KMT2D and SETD2 germline mutations have little impact on DNAme profiles. In contrast, the overlapping DNAme alterations downstream of NSD1 or DNMT3 mutations underlines functional links, more specifically between NSD1 and DNMT3B at heterochromatin regions or DNMT3A at regulatory elements. Together, these data indicate certain discrepancy with the mechanisms described in animal models or the existence of redundant or complementary functions unforeseen in humans.

Decreased expression of DNA methyltransferases in the testes of patients with non-obstructive azoospermia leads to changes in global DNA methylation levels

2019 ◽  
Vol 31 (8) ◽  
pp. 1386 ◽  
Author(s):  
Fatma Uysal ◽  
Gokhan Akkoyunlu ◽  
Saffet Ozturk
Keyword(s):  
Dna Methylation ◽  
Male Infertility ◽  
De Novo ◽  
Biological Effects ◽  
Testicular Biopsy ◽  
Round Spermatid ◽  
Dna Methyltransferases ◽  
Global Dna Methylation ◽  
Obstructive Azoospermia ◽  
Spermatogenic Cells

DNA methylation plays key roles in epigenetic regulation during mammalian spermatogenesis. DNA methyltransferases (DNMTs) function in de novo and maintenance methylation processes by adding a methyl group to the fifth carbon atom of the cytosine residues within cytosine–phosphate–guanine (CpG) and non-CpG dinucleotide sites. Azoospermia is one of the main causes of male infertility, and is classified as obstructive (OA) or non-obstructive (NOA) azoospermia based on histopathological characteristics. The molecular background of NOA is still largely unknown. DNA methylation performed by DNMTs is implicated in the transcriptional regulation of spermatogenesis-related genes. The aim of the present study was to evaluate the cellular localisation and expression levels of the DNMT1, DNMT3A and DNMT3B proteins, as well as global DNA methylation profiles in testicular biopsy samples obtained from men with various types of NOA, including hypospermatogenesis (hyposperm), round spermatid (RS) arrest, spermatocyte (SC) arrest and Sertoli cell-only (SCO) syndrome. In the testicular biopsy samples, DNMT1 expression and global DNA methylation levels decreased gradually from the hyposperm to SCO groups (P<0.05). DNMT3A expression was significantly decreased in the RS arrest, SC arrest and SCO groups compared with the hyposperm group (P<0.05). DNMT3B expression was significantly lower in the RS arrest and SCO groups than in the hyposperm group (P<0.05). Although both DNMT1 and DNMT3A were localised in the cytoplasm and nucleus of the spermatogenic cells, staining for DNMT3B was more intensive in the nucleus of spermatogenic cells. In conclusion, the findings suggest that significant changes in DNMT expression and global DNA methylation levels in spermatogenic cells may contribute to development of male infertility in the NOA groups. Further studies are needed to determine the molecular biological effects of the altered DNMT expression and DNA methylation levels on development of male infertility.

scholarly journals Epigenetic marking and repression of porcine endogenous retroviruses

2013 ◽  
Vol 94 (5) ◽  
pp. 960-970 ◽  
Author(s):  
Gernot Wolf ◽  
Anders Lade Nielsen ◽  
Jacob Giehm Mikkelsen ◽  
Finn Skou Pedersen
Keyword(s):  
Dna Methylation ◽  
De Novo ◽  
Germ Line ◽  
Mammalian Species ◽  
Histone Deacetylation ◽  
Endogenous Retroviruses ◽  
Primer Binding Site ◽  
Retroviral Transduction ◽  
Embryonic Germ Cells ◽  
Epigenetic Repression

Endogenous retroviruses (ERVs) are remnants of retroviral germ line infections and have been identified in all mammals investigated so far. Although the majority of ERVs are degenerated, some mammalian species, such as mice and pigs, carry replication-competent ERVs capable of forming infectious viral particles. In mice, ERVs are silenced by DNA methylation and histone modifications and some exogenous retroviruses were shown to be transcriptionally repressed after integration by a primer-binding site (PBS) targeting mechanism. However, epigenetic repression of porcine ERVs (PERVs) has remained largely unexplored so far. In this study, we screened the pig genome for PERVs using LTRharvest, a tool for de novo detection of ERVs, and investigated various aspects of epigenetic repression of three unrelated PERV families. We found that these PERV families are differentially up- or downregulated upon chemical inhibition of DNA methylation and histone deacetylation in cultured porcine cells. Furthermore, chromatin immunoprecipitation analysis revealed repressive histone methylation marks at PERV loci in primary porcine embryonic germ cells and immortalized embryonic kidney cells. PERV elements belonging to the PERV-γ1 family, which is the only known PERV family that has remained active up to the present, were marked by significantly higher levels of histone methylations than PERV-γ2 and PERV-β3 proviruses. Finally, we tested three PERV-associated PBS sequences for repression activity in murine and porcine cells using retroviral transduction experiments and showed that none of these PBS sequences induced immediate transcriptional silencing in the tested primary porcine cells.

scholarly journals The Roles of Human DNA Methyltransferases and Their Isoforms in Shaping the Epigenome

Genes ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 172 ◽  
Author(s):  
Hemant Gujar ◽  
Daniel Weisenberger ◽  
Gangning Liang
Keyword(s):  
Dna Methylation ◽  
Cytosine Methylation ◽  
De Novo ◽  
Ring Finger ◽  
Dna Methyltransferases ◽  
Epigenetic Modifications ◽  
Hard Copy ◽  
Physiological Processes ◽  
New Gene ◽  
Cpg Dinucleotide

A DNA sequence is the hard copy of the human genome and it is a driving force in determining the physiological processes in an organism. Concurrently, the chemical modification of the genome and its related histone proteins is dynamically involved in regulating physiological processes and diseases, which overall constitutes the epigenome network. Among the various forms of epigenetic modifications, DNA methylation at the C-5 position of cytosine in the cytosine–guanine (CpG) dinucleotide is one of the most well studied epigenetic modifications. DNA methyltransferases (DNMTs) are a family of enzymes involved in generating and maintaining CpG methylation across the genome. In mammalian systems, DNA methylation is performed by DNMT1 and DNMT3s (DNMT3A and 3B). DNMT1 is predominantly involved in the maintenance of DNA methylation during cell division, while DNMT3s are involved in establishing de novo cytosine methylation and maintenance in both embryonic and somatic cells. In general, all DNMTs require accessory proteins, such as ubiquitin-like containing plant homeodomain (PHD) and really interesting new gene (RING) finger domain 1 (UHRF1) or DNMT3-like (DNMT3L), for their biological function. This review mainly focuses on the role of DNMT3B and its isoforms in de novo methylation and maintenance of DNA methylation, especially with respect to their role as an accessory protein.

scholarly journals Structural insights into CpG-specific DNA methylation by human DNA methyltransferase 3B

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
Keyword(s):  
Dna Methylation ◽  
Dna Methyltransferase ◽  
Cytosine Methylation ◽  
Catalytic Domain ◽  
De Novo ◽  
Water Channel ◽  
Dna Methyltransferases ◽  
Structural Basis ◽  
Cpg Sites ◽  
Methylation Patterns

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.

Dynamics in the expression of epigenetic modifiers and histone modifications in perinatal rat germ cells during de novo DNA methylation†

2020 ◽  
Author(s):  
Arlette Rwigemera ◽  
Rhizlane El omri-Charai ◽  
Laetitia L Lecante ◽  
Geraldine Delbes
Keyword(s):  
Dna Methylation ◽  
Germ Cell ◽  
Histone Modifications ◽  
Germ Cells ◽  
Posttranslational Modifications ◽  
Fluorescent Protein ◽  
De Novo ◽  
Expression Patterns ◽  
Dna Methyltransferases ◽  
Epigenetic Modifiers

Abstract Epigenetic reprogramming during perinatal germ cell development is essential for genomic imprinting and cell differentiation; however, the actors of this key event and their dynamics are poorly understood in rats. Our study aimed to characterize the expression patterns of epigenetic modifiers and the changes in histone modifications in rat gonocytes at the time of de novo DNA methylation. Using transgenic rats expressing Green Fluorescent Protein (GFP) specifically in germ cells, we purified male gonocytes by fluorescent activated cell sorting at various stages of perinatal development and established the transcriptomic profile of 165 epigenetic regulators. Using immunofluorescence on gonad sections, we tracked six histone modifications in rat male and female perinatal germ cells over time, including methylation of histone H3 on lysines 27, 9, and 4; ubiquitination of histone H2A on lysine119; and acetylation of histone H2B on lysine 20. The results revealed the dynamics in the expression of ten-eleven translocation enzymes and DNA methyltransferases in male gonocytes at the time of de novo DNA methylation. Moreover, our transcriptomic data indicate a decrease in histone ubiquitination and methylation coinciding with the beginning of de novo DNA methylation. Decreases in H2AK119Ub and H3K27me3 were further confirmed by immunofluorescence in the male germ cells but were not consistent for all H3 methylation sites examined. Together, our data highlighted transient chromatin remodeling involving histone modifications during de novo DNA methylation. Further studies addressing how these dynamic changes in histone posttranslational modifications could guide de novo DNA methylation will help explain the complex establishment of the male germ cell epigenome.

A cluster of four genes selectively expressed in the male germ line of Drosophila melanogaster

1991 ◽  
Vol 35 (2) ◽  
pp. 143-151 ◽  
Author(s):  
Rainer Kuhn ◽  
Claudia Kuhn ◽  
Dagmar Börsch ◽  
Karl Heinz Glätzer ◽  
Ulrich Schäfer ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Germ Line ◽  
Male Germ Line
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