scholarly journals Transcriptomics of Meiosis in the Male Mouse

2021 ◽  
Vol 9 ◽  
Author(s):  
Adriana Geisinger ◽  
Rosana Rodríguez-Casuriaga ◽  
Ricardo Benavente
Keyword(s):  
Sex Chromosome ◽  
Expression Patterns ◽  
Male Meiosis ◽  
Practical Reasons ◽  
Isolated Cells ◽  
Meiotic Sex Chromosome Inactivation ◽  
Technical Advances ◽  
Non Coding Rnas ◽  
Flow Cytometry Sorting

Molecular studies of meiosis in mammals have been long relegated due to some intrinsic obstacles, namely the impossibility to reproduce the process in vitro, and the difficulty to obtain highly pure isolated cells of the different meiotic stages. In the recent years, some technical advances, from the improvement of flow cytometry sorting protocols to single-cell RNAseq, are enabling to profile the transcriptome and its fluctuations along the meiotic process. In this mini-review we will outline the diverse methodological approaches that have been employed, and some of the main findings that have started to arise from these studies. As for practical reasons most studies have been carried out in males, and mostly using mouse as a model, our focus will be on murine male meiosis, although also including specific comments about humans. Particularly, we will center on the controversy about gene expression during early meiotic prophase; the widespread existing gap between transcription and translation in meiotic cells; the expression patterns and potential roles of meiotic long non-coding RNAs; and the visualization of meiotic sex chromosome inactivation from the RNAseq perspective.

scholarly journals On the Origin and Evolution of Drosophila New Genes during Spermatogenesis

Genes ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1796
Author(s):  
Qianwei Su ◽  
Huangyi He ◽  
Qi Zhou
Keyword(s):  
X Chromosome ◽  
Sex Chromosome ◽  
Expression Patterns ◽  
Cell Level ◽  
Origin And Evolution ◽  
Functional Studies ◽  
New Genes ◽  
Meiotic Sex Chromosome Inactivation ◽  
New Gene ◽  
Cell Transcriptome

The origin of functional new genes is a basic biological process that has significant contribution to organismal diversity. Previous studies in both Drosophila and mammals showed that new genes tend to be expressed in testes and avoid the X chromosome, presumably because of meiotic sex chromosome inactivation (MSCI). Here, we analyze the published single-cell transcriptome data of Drosophila adult testis and find an enrichment of male germline mitotic genes, but an underrepresentation of meiotic genes on the X chromosome. This can be attributed to an excess of autosomal meiotic genes that were derived from their X-linked mitotic progenitors, which provides direct cell-level evidence for MSCI in Drosophila. We reveal that new genes, particularly those produced by retrotransposition, tend to exhibit an expression shift toward late spermatogenesis compared with their parental copies, probably due to the more intensive sperm competition or sexual conflict. Our results dissect the complex factors including age, the origination mechanisms and the chromosomal locations that influence the new gene origination and evolution in testes, and identify new gene cases that show divergent cell-level expression patterns from their progenitors for future functional studies.

scholarly journals Meiotic Double-Strand Break Processing and Crossover Patterning Are Regulated in a Sex-Specific Manner by BRCA1–BARD1 in Caenorhabditis elegans

Genetics ◽  
2020 ◽  
Vol 216 (2) ◽  
pp. 359-379 ◽  
Author(s):  
Qianyan Li ◽  
Sara Hariri ◽  
JoAnne Engebrecht
Keyword(s):  
Caenorhabditis Elegans ◽  
Meiotic Recombination ◽  
Sex Chromosome ◽  
Strand Break ◽  
Male Meiosis ◽  
Female Meiosis ◽  
Link Type ◽  
Meiotic Sex Chromosome Inactivation ◽  
Specific Manner ◽  
Dna End Resection

Meiosis is regulated in a sex-specific manner to produce two distinct gametes, sperm and oocytes, for sexual reproduction. To determine how meiotic recombination is regulated in spermatogenesis, we analyzed the meiotic phenotypes of mutants in the tumor suppressor E3 ubiquitin ligase BRC-1-BRD-1 complex in Caenorhabditis elegans male meiosis. Unlike in mammals, this complex is not required for meiotic sex chromosome inactivation, the process whereby hemizygous sex chromosomes are transcriptionally silenced. Interestingly, brc-1 and brd-1 mutants show meiotic recombination phenotypes that are largely opposing to those previously reported for female meiosis. Fewer meiotic recombination intermediates marked by the recombinase RAD-51 were observed in brc-1 and brd-1 mutants, and the reduction in RAD-51 foci could be suppressed by mutation of nonhomologous-end-joining proteins. Analysis of GFP::RPA-1 revealed fewer foci in the brc-1brd-1 mutant and concentration of BRC-1-BRD-1 to sites of meiotic recombination was dependent on DNA end resection, suggesting that the complex regulates the processing of meiotic double-strand breaks to promote repair by homologous recombination. Further, BRC-1-BRD-1 is important to promote progeny viability when male meiosis is perturbed by mutations that block the pairing and synapsis of different chromosome pairs, although the complex is not required to stabilize the RAD-51 filament as in female meiosis under the same conditions. Analyses of crossover designation and formation revealed that BRC-1-BRD-1 inhibits supernumerary COs when meiosis is perturbed. Together, our findings suggest that BRC-1-BRD-1 regulates different aspects of meiotic recombination in male and female meiosis.

scholarly journals Extensive meiotic asynapsis in mice antagonises meiotic silencing of unsynapsed chromatin and consequently disrupts meiotic sex chromosome inactivation

2008 ◽  
Vol 182 (2) ◽  
pp. 263-276 ◽  
Author(s):  
Shantha K. Mahadevaiah ◽  
Déborah Bourc'his ◽  
Dirk G. de Rooij ◽  
Timothy H. Bestor ◽  
James M.A. Turner ◽  
...  
Keyword(s):  
Sex Chromosome ◽  
Male Meiosis ◽  
Chromosome Inactivation ◽  
Null Mouse ◽  
Dna Double Strand Breaks ◽  
Meiotic Silencing ◽  
Meiotic Sex Chromosome Inactivation ◽  
Y Chromosomes ◽  
Meiotic Dsbs ◽  
Sex Chromosome Inactivation

Chromosome synapsis during zygotene is a prerequisite for the timely homologous recombinational repair of meiotic DNA double-strand breaks (DSBs). Unrepaired DSBs are thought to trigger apoptosis during midpachytene of male meiosis if synapsis fails. An early pachytene response to asynapsis is meiotic silencing of unsynapsed chromatin (MSUC), which, in normal males, silences the X and Y chromosomes (meiotic sex chromosome inactivation [MSCI]). In this study, we show that MSUC occurs in Spo11-null mouse spermatocytes with extensive asynapsis but lacking meiotic DSBs. In contrast, three mutants (Dnmt3l, Msh5, and Dmc1) with high levels of asynapsis and numerous persistent unrepaired DSBs have a severely impaired MSUC response. We suggest that MSUC-related proteins, including the MSUC initiator BRCA1, are sequestered at unrepaired DSBs. All four mutants fail to silence the X and Y chromosomes (MSCI failure), which is sufficient to explain the midpachytene apoptosis. Apoptosis does not occur in mice with a single additional asynapsed chromosome with unrepaired meiotic DSBs and no disturbance of MSCI.

scholarly journals Epigenetic regulation in male germ cells

Reproduction ◽  
2008 ◽  
Vol 136 (2) ◽  
pp. 131-146 ◽  
Author(s):  
Natasha M Zamudio ◽  
Suyinn Chong ◽  
Moira K O'Bryan
Keyword(s):  
Germ Cells ◽  
Epigenetic Regulation ◽  
Sex Chromosome ◽  
Current Knowledge ◽  
Regulation Of Gene Expression ◽  
Male Meiosis ◽  
Paternal Effects ◽  
Male Germ Cells ◽  
Epigenetic Effects ◽  
Meiotic Sex Chromosome Inactivation

In recent years, it has become increasingly clear that epigenetic regulation of gene expression is critical during spermatogenesis. In this review, the epigenetic regulation and the consequences of its aberrant regulation during mitosis, meiosis and spermiogenesis are described. The current knowledge on epigenetic modifications that occur during male meiosis is discussed, with special attention on events that define meiotic sex chromosome inactivation. Finally, the recent studies focused on transgenerational and paternal effects in mice and humans are discussed. In many cases, these epigenetic effects resulted in impaired fertility and potentially long-ranging affects underlining the importance of research in this area.

scholarly journals C. elegans BRC-1-BRD-1 functions at an early step of DSB processing and inhibits supernumerary crossovers during male meiosis

2020 ◽  
Author(s):  
Qianyan Li ◽  
Sara Hariri ◽  
JoAnne Engebrecht
Keyword(s):  
Meiotic Recombination ◽  
Sex Chromosome ◽  
Male Meiosis ◽  
Nonhomologous End Joining ◽  
End Joining ◽  
Female Meiosis ◽  
Strand Breaks ◽  
C Elegans ◽  
Meiotic Sex Chromosome Inactivation ◽  
Dna End Resection

AbstractMeiosis is regulated in a sex-specific manner to produce two distinct gametes, sperm and oocytes, for sexual reproduction. To determine how meiotic recombination is regulated in spermatogenesis, we analyzed the meiotic phenotypes of mutants in the tumor suppressor E3 ubiquitin ligase BRC-1-BRD-1 complex in Caenorhabditis elegans male meiosis. Unlike in mammals, this complex is not required for meiotic sex chromosome inactivation, the process whereby hemizygous sex chromosomes are transcriptionally silenced. Interestingly, brc-1 and brd-1 mutants showed meiotic recombination phenotypes that are largely opposing to those previously reported for female meiosis. Fewer meiotic recombination foci marked by the recombinase RAD-51 were observed in brc-1 and brd-1 mutants, and the reduction in RAD-51 foci can be suppressed by mutation of nonhomologous end joining proteins. We show that concentration of BRC-1-BRD-1 to sites of meiotic recombination is dependent on DNA end resection, suggesting that BRC-1-BRD-1 regulates the processing of meiotic double strand breaks to promote repair by homologous recombination, similar to a role for the complex in somatic cells. We also show that BRC-1-BRD-1 is important to promote progeny viability when male meiosis is perturbed by mutations that block the pairing and synapsis of different chromosome pairs, although the complex is not required to stabilize the RAD-51 filament as in female meiosis under the same conditions. Analyses of crossover designation and formation reveal that BRC-1-BRD-1 inhibits supernumerary crossovers when meiosis is perturbed. Together, our findings suggest that BRC-1-BRD-1 regulates different aspects of meiotic recombination in male and female meiosis.

scholarly journals LINC00261 Is Differentially Expressed in Pancreatic Cancer Subtypes and Regulates a Pro-Epithelial Cell Identity

Cancers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1227 ◽  
Author(s):  
Agnes Dorn ◽  
Markus Glaß ◽  
Carolin T. Neu ◽  
Beate Heydel ◽  
Stefan Hüttelmaier ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Transforming Growth Factor ◽  
Human Cancer ◽  
Expression Patterns ◽  
Transcriptional Analysis ◽  
Mesenchymal Transition ◽  
Cancer Subtypes ◽  
Dismal Prognosis ◽  
Non Coding Rnas

Pancreatic adenocarcinoma (PDAC) is one of the major causes of cancer-associated deaths worldwide, with a dismal prognosis that has not significantly changed over the last decades. Transcriptional analysis has provided valuable insights into pancreatic tumorigenesis. Specifically, pancreatic cancer subtypes were identified, characterized by specific mutations and gene expression changes associated with differences in patient survival. In addition to differentially regulated mRNAs, non-coding RNAs, including long non-coding RNAs (lncRNAs), were shown to have subtype-specific expression patterns. Hence, we aimed to characterize prognostic lncRNAs with deregulated expression in the squamous subtype of PDAC, which has the worst prognosis. Extensive in silico analyses followed by in vitro experiments identified long intergenic non-coding RNA 261 (LINC00261) as a downregulated lncRNA in the squamous subtype of PDAC, which is generally associated with transforming growth factor β (TGFβ) signaling in human cancer cells. Its genomic neighbor, the transcription factor forkhead box protein A2 (FOXA2), regulated LINC00261 expression by direct binding of the LINC00261 promoter. CRISPR-mediated knockdown and promoter knockout validated the importance of LINC00261 in TGFβ-mediated epithelial–mesenchymal transition (EMT) and established the epithelial marker E-cadherin, an important cell adhesion protein, as a downstream target of LINC00261. Consequently, depletion of LINC00261 enhanced motility and invasiveness of PANC-1 cells in vitro. Altogether, our data suggest that LINC00261 is an important tumor-suppressive lncRNA in PDAC that is involved in maintaining a pro-epithelial state associated with favorable disease outcome.

scholarly journals Epigenetic Dysregulation of Mammalian Male Meiosis Caused by Interference of Recombination and Synapsis

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2311
Author(s):  
Roberto de la Fuente ◽  
Florencia Pratto ◽  
Abrahan Hernández-Hernández ◽  
Marcia Manterola ◽  
Pablo López-Jiménez ◽  
...  
Keyword(s):  
Transcriptional Regulation ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Male Meiosis ◽  
Epigenetic Marks ◽  
Prophase I ◽  
Recombination Proteins ◽  
Meiotic Sex Chromosome Inactivation ◽  
Y Chromosomes ◽  
Genes Encoding

Meiosis involves a series of specific chromosome events, namely homologous synapsis, recombination, and segregation. Disruption of either recombination or synapsis in mammals results in the interruption of meiosis progression during the first meiotic prophase. This is usually accompanied by a defective transcriptional inactivation of the X and Y chromosomes, which triggers a meiosis breakdown in many mutant models. However, epigenetic changes and transcriptional regulation are also expected to affect autosomes. In this work, we studied the dynamics of epigenetic markers related to chromatin silencing, transcriptional regulation, and meiotic sex chromosome inactivation throughout meiosis in knockout mice for genes encoding for recombination proteins SPO11, DMC1, HOP2 and MLH1, and the synaptonemal complex proteins SYCP1 and SYCP3. These models are defective in recombination and/or synapsis and promote apoptosis at different stages of progression. Our results indicate that impairment of recombination and synapsis alter the dynamics and localization pattern of epigenetic marks, as well as the transcriptional regulation of both autosomes and sex chromosomes throughout prophase-I progression. We also observed that the morphological progression of spermatocytes throughout meiosis and the dynamics of epigenetic marks are processes that can be desynchronized upon synapsis or recombination alteration. Moreover, we detected an overlap of early and late epigenetic signatures in most mutants, indicating that the normal epigenetic transitions are disrupted. This can alter the transcriptional shift that occurs in spermatocytes in mid prophase-I and suggest that the epigenetic regulation of sex chromosomes, but also of autosomes, is an important factor in the impairment of meiosis progression in mammals.

scholarly journals The circular RNA circSLC7A11 functions as a mir-330-3p sponge to accelerate hepatocellular carcinoma progression by regulating cyclin-dependent kinase 1 expression

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yu Huang ◽  
Wenhao Ge ◽  
Yuan Ding ◽  
Lufei Zhang ◽  
Jiarong Zhou ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cancer Progression ◽  
Expression Patterns ◽  
Circular Rna ◽  
Northern Blotting ◽  
Luciferase Reporter ◽  
Circular Rnas ◽  
Non Coding Rnas

Abstract Background Circular RNAs (circRNAs), which are endogenous non-coding RNAs, are associated with various biological processes including development, homeostatic maintenance, and pathological responses. Accumulating evidence has implicated non-coding RNAs in cancer progression, and the role of circRNAs in particular has drawn wide attention. However, circRNA expression patterns and functions in hepatocellular carcinoma (HCC) remain poorly understood. Methods CircRNA sequencing was performed to screen differentially expressed circRNAs in HCC. Northern blotting, quantitative real-time polymerase chain reaction, nucleocytoplasmic fractionation, and fluorescence in situ hybridization analyses were conducted to evaluate the expression and localization of circSLC7A11 in HCC tissues and cells. CircSLC7A11 expression levels were modified in cultured HCC cell lines to explore the association between the expression of circSLC7A11 and the malignant behavior of these cells using several cell-based assays. The modified cells were implanted into immunocompetent nude mice to assess tumor growth and metastasis in vivo. We applied bioinformatics methods, RNA pulldown, RNA immunoprecipitation, and luciferase reporter assays to explore the mechanisms of circSLC7A11 in HCC. Results CircSLC7A11 (hsa_circ_0070975) was conserved and dramatically overexpressed in HCC tissues and cells. HCC patients showing high circSLC7A11 expression had worse prognoses. Our in vitro and in vivo experiments showed that circSLC7A11 markedly accelerated HCC progression and metastasis through the circSLC7A11/miR-330-3p/CDK1 axis. Conclusions The acceleration of HCC progression and metastasis by circSLC7A11 through the circSLC7A11/miR-330-3p/CDK1 axis suggests that circSLC7A11 is a potential novel diagnostic and therapeutic target for HCC treatment.

scholarly journals The male germline-specific protein MAPS is indispensable for pachynema progression and fertility

2021 ◽  
Vol 118 (8) ◽  
pp. e2025421118
Author(s):  
Miao Li ◽  
Jiahuan Zheng ◽  
Gaopeng Li ◽  
Zexiong Lin ◽  
Dongliang Li ◽  
...  
Keyword(s):  
Large Scale ◽  
Sex Chromosome ◽  
Strand Break ◽  
Specific Protein ◽  
Pachytene Stage ◽  
Protein Ubiquitination ◽  
Male Germline ◽  
Meiotic Sex Chromosome Inactivation ◽  
Pachytene Spermatocytes

Meiosis is a specialized cell division that creates haploid germ cells from diploid progenitors. Through differential RNA expression analyses, we previously identified a number of mouse genes that were dramatically elevated in spermatocytes, relative to their very low expression in spermatogonia and somatic organs. Here, we investigated in detail 1700102P08Rik, one of these genes, and independently conclude that it encodes a male germline-specific protein, in agreement with a recent report. We demonstrated that it is essential for pachynema progression in spermatocytes and named it male pachynema-specific (MAPS) protein. Mice lacking Maps (Maps−/−) suffered from pachytene arrest and spermatocyte death, leading to male infertility, whereas female fertility was not affected. Interestingly, pubertal Maps−/− spermatocytes were arrested at early pachytene stage, accompanied by defects in DNA double-strand break (DSB) repair, crossover formation, and XY body formation. In contrast, adult Maps−/− spermatocytes only exhibited partially defective crossover but nonetheless were delayed or failed in progression from early to mid- and late pachytene stage, resulting in cell death. Furthermore, we report a significant transcriptional dysregulation in autosomes and XY chromosomes in both pubertal and adult Maps−/− pachytene spermatocytes, including failed meiotic sex chromosome inactivation (MSCI). Further experiments revealed that MAPS overexpression in vitro dramatically decreased the ubiquitination levels of cellular proteins. Conversely, in Maps−/− pachytene cells, protein ubiquitination was dramatically increased, likely contributing to the large-scale disruption in gene expression in pachytene cells. Thus, MAPS is a protein essential for pachynema progression in male mice, possibly in mammals in general.

Development of an in vitro Model for the Study of the Response of Equine Tendon Fibroblasts to Injury and Medication

1997 ◽  
Vol 10 (01) ◽  
pp. 6-11 ◽  
Author(s):  
R. F. Rosenbusch ◽  
L. C. Booth ◽  
L. A. Dahlgren
Keyword(s):  
Electron Microscopy ◽  
Extracellular Matrix ◽  
Light Microscopy ◽  
Light And Electron Microscopy ◽  
Tendon Healing ◽  
Matrix Proteins ◽  
Isolated Cells ◽  
Superficial Digital Flexor Tendon ◽  
Vitro Model

SummaryEquine tendon fibroblasts were isolated from explants of superficial digital flexor tendon, subcultured and maintained in monolayers. The cells were characterized by light microscopy, electron microscopy and radiolabel studies for proteoglycan production. Two predominant cell morphologies were identified. The cells dedifferentiated toward a more spindle shape with repeated subcultures. Equine tendon fibroblasts were successfully cryopreserved and subsequently subcultured. The ability to produce proteoglycan was preserved.The isolated cells were identified as fibroblasts, based on their characteristic shape by light microscopy and ultrastructure and the active production of extracellular matrix proteins. Abundant rough endoplasmic reticulum and the production of extracellular matrix products demonstrated active protein production and export. Proteoglycans were measurable via liquid scintillation counting in both the cell-associated fraction and free in the supernatant. This model is currently being utilized to study the effects of polysulfated glycosaminoglycan on tendon healing. Future uses include studying the effects of other pharmaceuticals, such as hyaluronic acid, on tendon healing.A model was developed for in vitro investigations into tendon healing. Fibroblasts were isolated from equine superficial digital flexor tendons and maintained in monolayer culture. The tenocytes were characterized via light and electron microscopy. Proteoglycan production was measured, using radio-label techniques. The fibroblasts were cryopreserved and subsequently subcultured. The cells maintained their capacity for proteoglycan production, following repeated subculturing and cryopreservation.

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