scholarly journals Maintenance DNA methylation in pre-meiotic germ cells regulates meiotic prophase by facilitating homologous chromosome pairing

Development ◽  
2021 ◽  
Vol 148 (10) ◽  
Author(s):  
Yuki Takada ◽  
Ruken Yaman-Deveci ◽  
Takayuki Shirakawa ◽  
Jafar Sharif ◽  
Shin-ichi Tomizawa ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Germ Cells ◽  
Meiotic Prophase ◽  
De Novo ◽  
Pericentric Heterochromatin ◽  
Male Germ Cells ◽  
Homologous Chromosomes ◽  
Homologous Chromosome Pairing ◽  
Synaptic Failure

ABSTRACT Heterochromatin-related epigenetic mechanisms, such as DNA methylation, facilitate pairing of homologous chromosomes during the meiotic prophase of mammalian spermatogenesis. In pro-spermatogonia, de novo DNA methylation plays a key role in completing meiotic prophase and initiating meiotic division. However, the role of maintenance DNA methylation in the regulation of meiosis, especially in the adult, is not well understood. Here, we reveal that NP95 (also known as UHRF1) and DNMT1 – two essential proteins for maintenance DNA methylation – are co-expressed in spermatogonia and are necessary for meiosis in male germ cells. We find that Np95- or Dnmt1-deficient spermatocytes exhibit spermatogenic defects characterized by synaptic failure during meiotic prophase. In addition, assembly of pericentric heterochromatin clusters in early meiotic prophase, a phenomenon that is required for subsequent pairing of homologous chromosomes, is disrupted in both mutants. Based on these observations, we propose that DNA methylation, established in pre-meiotic spermatogonia, regulates synapsis of homologous chromosomes and, in turn, quality control of male germ cells. Maintenance DNA methylation, therefore, plays a role in ensuring faithful transmission of both genetic and epigenetic information to offspring.

scholarly journals MORC3, a novel MIWI2 association partner, as an epigenetic regulator of piRNA dependent transposon silencing in male germ cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kanako Kojima-Kita ◽  
Satomi Kuramochi-Miyagawa ◽  
Manabu Nakayama ◽  
Haruhiko Miyata ◽  
Steven E. Jacobsen ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Germ Cells ◽  
De Novo ◽  
Effector Proteins ◽  
P Element ◽  
Male Germ Cells ◽  
Transposon Silencing ◽  
Association Partner ◽  
Pirna Pathway

AbstractThe PIWI (P-element-induced wimpy testis)-interacting-RNA (piRNA) pathway plays a crucial role in the repression of TE (transposable element) expression via de novo DNA methylation in mouse embryonic male germ cells. Various proteins, including MIWI2 are involved in the process. TE silencing is ensured by piRNA-guided MIWI2 that recruits some effector proteins of the DNA methylation machinery to TE regions. However, the molecular mechanism underlying the methylation is complex and has not been fully elucidated. Here, we identified MORC3 as a novel associating partner of MIWI2 and also a nuclear effector of retrotransposon silencing via piRNA-dependent de novo DNA methylation in embryonic testis. Moreover, we show that MORC3 is important for transcription of piRNA precursors and subsequently affects piRNA production. Thus, we provide the first mechanistic insights into the role of this effector protein in the first stage of piRNA biogenesis in embryonic TE silencing mechanism.

scholarly journals Transcriptional states of retroelement-inserted regions and KRAB zinc finger protein association regulate DNA methylation of retroelements in human male germ cells

2021 ◽  
Author(s):  
Kei Fukuda ◽  
Yoshinori Makino ◽  
Satoru Kaneko ◽  
Yuki Okada ◽  
Kenji Ichiyanagi ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Zinc Finger ◽  
Germ Cells ◽  
Molecular Mechanisms ◽  
Zinc Finger Protein ◽  
De Novo ◽  
Primordial Germ Cells ◽  
Male Germ Cells ◽  
Human Male ◽  
Human Spermatogenesis

DNA methylation, repressive histone modifications, and PIWI-interacting RNAs are essential for controlling retroelement silencing in mammalian germ lines. Dysregulation of retroelement silencing is associated with male sterility. Although retroelement silencing mechanisms have been extensively studied in mouse germ cells, little progress has been made in humans. Here, we show that the Krüppel-associated box domain zinc finger proteins (KRAB-ZFPs) are associated with DNA methylation of retroelements in human primordial germ cells (hPGCs), and hominoid-specific retroelement SINE-VNTR-Alus (SVA) is subjected to transcription-directed de novo DNA methylation during human spermatogenesis. Furthermore, we show that the degree of de novo DNA methylation in SVAs varies among human individuals, which confers a significant inter-individual epigenetic variation in sperm. Collectively, our results provide potential molecular mechanisms for the regulation of retroelements in human male germ cells.

scholarly journals Genomic imprinting in germ cells: imprints are under control

Reproduction ◽  
2010 ◽  
Vol 140 (3) ◽  
pp. 411-423 ◽  
Author(s):  
Philippe Arnaud
Keyword(s):  
Dna Methylation ◽  
Genomic Imprinting ◽  
Germ Cells ◽  
Imprinted Genes ◽  
Regulatory Sequences ◽  
Sequence Specificity ◽  
Maternal Allele ◽  
Primary Sequence ◽  
Chromatin Configuration

The cis-acting regulatory sequences of imprinted gene loci, called imprinting control regions (ICRs), acquire specific imprint marks in germ cells, including DNA methylation. These epigenetic imprints ensure that imprinted genes are expressed exclusively from either the paternal or the maternal allele in offspring. The last few years have witnessed a rapid increase in studies on how and when ICRs become marked by and subsequently maintain such epigenetic modifications. These novel findings are summarised in this review, which focuses on the germline acquisition of DNA methylation imprints and particularly on the combined role of primary sequence specificity, chromatin configuration, non-histone proteins and transcriptional events.

Developmental changes in DNA methylation of the male germ cells in foetal and prepuberal mice

1998 ◽  
Vol 90 (1) ◽  
pp. 110-110
Author(s):  
Claire A. Bourgeois ◽  
Herve Coffigny ◽  
Michèle Ricoul ◽  
Bernard Malfoy ◽  
Bernard Dutrillaux
Keyword(s):  
Dna Methylation ◽  
Germ Cells ◽  
Developmental Changes ◽  
Male Germ Cells

scholarly journals Brown Fat Dnmt3b Deficiency Ameliorates Obesity in Female Mice

Life ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1325
Author(s):  
Fenfen Li ◽  
Xin Cui ◽  
Jia Jing ◽  
Shirong Wang ◽  
Huidong Shi ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Energy Expenditure ◽  
Knockout Mice ◽  
Dna Methyltransferase ◽  
De Novo ◽  
Brown Fat ◽  
Chow Diet ◽  
Female Mice ◽  
Diet Induced Obesity

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.

scholarly journals Mammalian Protein SCP1 Forms Synaptonemal Complex-like Structures in the Absence of Meiotic Chromosomes

2005 ◽  
Vol 16 (1) ◽  
pp. 212-217 ◽  
Author(s):  
Rupert Öllinger ◽  
Manfred Alsheimer ◽  
Ricardo Benavente
Keyword(s):  
Chromosome Segregation ◽  
Meiotic Prophase ◽  
Experimental Conditions ◽  
Homologous Chromosomes ◽  
Meiotic Chromosomes ◽  
Heterologous System ◽  
Primary Determinant ◽  
Specific Proteins ◽  
Mammalian Protein

Synaptonemal complexes (SCs) are evolutionary conserved, meiosis-specific structures that play a central role in synapsis of homologous chromosomes, chiasmata distribution, and chromosome segregation. However, it is still for the most part unclear how SCs do assemble during meiotic prophase. Major components of mammalian SCs are the meiosis-specific proteins SCP1, 2, and 3. To investigate the role of SCP1 in SC assembly, we expressed SCP1 in a heterologous system, i.e., in COS-7 cells that normally do not express SC proteins. Notably, under these experimental conditions SCP1 is able to form structures that closely resemble SCs (i.e., polycomplexes). Moreover, we show that mutations that modify the length of the central α-helical domain of SCP1 influence the width of polycomplexes. Finally, we demonstrate that deletions of the nonhelical N- or C-termini both affect polycomplex assembly, although in a different manner. We conclude that SCP1 is a primary determinant of SC assembly that plays a key role in synapsis of homologous chromosomes.

scholarly journals Overexpression of peroxisomal testis-specific 1 protein induces germ cell apoptosis and leads to infertility in male mice

2011 ◽  
Vol 22 (10) ◽  
pp. 1766-1779 ◽  
Author(s):  
Karina Kaczmarek ◽  
Maja Studencka ◽  
Andreas Meinhardt ◽  
Krzysztof Wieczerzak ◽  
Sven Thoms ◽  
...  
Keyword(s):  
Cell Death ◽  
Germ Cell ◽  
Germ Cells ◽  
Specific Gene ◽  
Male Mice ◽  
Terminal Part ◽  
Male Germ Cells ◽  
Germ Cell Apoptosis ◽  
Induced Apoptosis

 Peroxisomal testis-specific 1 gene (Pxt1) is the only male germ cell–specific gene that encodes a peroxisomal protein known to date. To elucidate the role of Pxt1 in spermatogenesis, we generated transgenic mice expressing a c-MYC-PXT1 fusion protein under the control of the PGK2 promoter. Overexpression of Pxt1 resulted in induction of male germ cells’ apoptosis mainly in primary spermatocytes, finally leading to male infertility. This prompted us to analyze the proapoptotic character of mouse PXT1, which harbors a BH3-like domain in the N-terminal part. In different cell lines, the overexpression of PXT1 also resulted in a dramatic increase of apoptosis, whereas the deletion of the BH3-like domain significantly reduced cell death events, thereby confirming that the domain is functional and essential for the proapoptotic activity of PXT1. Moreover, we demonstrated that PXT1 interacts with apoptosis regulator BAT3, which, if overexpressed, can protect cells from the PXT1-induced apoptosis. The PXT1-BAT3 association leads to PXT1 relocation from the cytoplasm to the nucleus. In summary, we demonstrated that PXT1 induces apoptosis via the BH3-like domain and that this process is inhibited by BAT3.

Effects of ten–eleven translocation 1 (Tet1) on DNA methylation and gene expression in chicken primordial germ cells

2019 ◽  
Vol 31 (3) ◽  
pp. 509 ◽  
Author(s):  
Minli Yu ◽  
Dongfeng Li ◽  
Wanyan Cao ◽  
Xiaolu Chen ◽  
Wenxing Du
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Germ Cells ◽  
Dna Methyltransferase ◽  
Primordial Germ Cells ◽  
Dna Demethylation ◽  
Caveolin 1 ◽  
Expression Of Genes ◽  
Deleted In Azoospermia

Ten–eleven translocation 1 (Tet1) is involved in DNA demethylation in primordial germ cells (PGCs); however, the precise regulatory mechanism remains unclear. In the present study the dynamics of 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) in developing PGCs and the role of Tet1 in PGC demethylation were analysed. Results show that 5mC levels dropped significantly after embryonic Day 4 (E4) and 5hmC levels increased reaching a peak at E5–E5.5. Interestingly, TET1 protein was highly expressed during E5 to E5.5, which showed a consistent trend with 5hmC. The expression of pluripotency-associated genes (Nanog, PouV and SRY-box 2 (Sox2)) and germ cell-specific genes (caveolin 1 (Cav1), piwi-like RNA-mediated gene silencing 1 (Piwi1) and deleted in azoospermia-like (Dazl)) was upregulated after E5, whereas the expression of genes from the DNA methyltransferase family was decreased. Moreover, the Dazl gene was highly methylated in early PGCs and then gradually hypomethylated. Knockdown of Tet1 showed impaired survival and proliferation of PGCs, as well as increased 5mC levels and reduced 5hmC levels. Further analysis showed that knockdown of Tet1 led to elevated DNA methylation levels of Dazl and downregulated gene expression including Dazl. Thus, this study reveals the dynamic epigenetic reprogramming of chicken PGCs invivo and the molecular mechanism of Tet1 in regulating genomic DNA demethylation and hypomethylation of Dazl during PGC development.

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.

Sign in / Sign up

Export Citation Format

Share Document