RESUMO
Rationale: Spermatogenesis is a highly organized cell differentiation process in mammals, involving mitosis, meiosis, and spermiogenesis. DIS3L2, which is primarily expressed in the cytoplasm, is an RNA exosome-independent ribonuclease. In female mice, Dis3l2-deficient oocytes fail to resume meiosis, resulting in arrest at the germinal vesicle stage and complete infertility. However, the role of DIS3L2 in germ cell development in males has remained largely unexplored. Methods: We established a pre-meiotic germ cell conditional knockout mouse model and investigated the biological function of DIS3L2 in spermatogenesis and male fertility through bulk RNA-seq and scRNA-seq analyses. Results: This study unveils that conditional ablation of Dis3l2 in pre-meiotic germ cells with Stra8-Cre mice impairs spermatogonial differentiation and hinders spermatocyte meiotic progression coupled with cell apoptosis. Such conditional ablation leads to defective spermatogenesis and sterility in adults. Bulk RNA-seq analysis revealed that Dis3l2 deficiency significantly disrupted the transcriptional expression pattern of genes related to the cell cycle, spermatogonial differentiation, and meiosis in Dis3l2 conditional knockout testes. Additionally, scRNA-seq analysis indicated that absence of DIS3L2 in pre-meiotic germ cells causes disrupted RNA metabolism, downregulated expression of cell cycle genes, and aberrant expression of spermatogonial differentiation genes, impeding spermatogonial differentiation. In meiotic spermatocytes, loss of DIS3L2 results in disturbed RNA metabolism, abnormal translation, and disrupted meiotic genes that perturb meiotic progression and induce cell apoptosis, leading to subsequent failure of spermatogenesis and male infertility. Conclusions: Collectively, these findings highlight the critical role of DIS3L2 ribonuclease-mediated RNA degradation in safeguarding the correct transcriptome during spermatogonial differentiation and spermatocyte meiotic progression, thus ensuring normal spermatogenesis and male fertility.
Assuntos
Infertilidade Masculina , Meiose , Camundongos Knockout , Espermatogênese , Animais , Masculino , Espermatogênese/genética , Camundongos , Meiose/genética , Infertilidade Masculina/genética , Infertilidade Masculina/metabolismo , Diferenciação Celular , Testículo/metabolismo , Espermatócitos/metabolismo , Apoptose/genética , Espermatogônias/metabolismo , Ribonucleases/metabolismo , Ribonucleases/genética , Feminino , Camundongos Endogâmicos C57BL , Células Germinativas/metabolismoRESUMO
TKTL1 is a crucial regulatory enzyme in the pentose phosphate pathway (PPP) and plays a significant role in energy synthesis. It is expressed in various tumour tissues, with its expression level closely associated with tumour invasion, metastasis and prognosis. Recent studies utilising proteomic analysis and other methods have highlighted the noteworthy expression of the TKTL1 gene in germ cells, particularly in spermatogonia and ovarian cells. Consequently, this article reviews the molecular characteristics of TKTL1 and its expression in germ cells to provide a reference for research on TKTL1 beyond tumour cells.
Assuntos
Transcetolase , Animais , Feminino , Masculino , Transcetolase/genética , Transcetolase/metabolismo , Humanos , Células Germinativas/metabolismo , Ovário/metabolismoRESUMO
Honeybees (Apis mellifera) are a keystone species for managed pollination and the production of hive products. Eusociality in honeybees leads to much of the reproduction in a hive driven by the queen. Queen bees have two large active ovaries that can produce large numbers of eggs if conditions are appropriate. These ovaries are also active throughout the long lives of these insects, up to 5â years in some cases. Recent studies have indicated that the germline precursors of the adult honeybee queen ovary are organized into 8-cell clusters, joined together by a polyfusome; a cytoplasmic bridge. To understand the origin of these clusters, and trace the development of the honeybee queen ovary, we examined the cell types and regionalization of the developing larval and pupal queen ovaries. We used established (nanos and castor), and novel (odd skipped) gene expression markers to determine regions of the developing ovary. Primordial germline cells develop in the honeybee embryo and are organized into ovary structures before the embryo hatches. The ovary is regionalized by larval stage 3 into terminal filaments and germaria. At this stage, clusters of germline cells in the germaria are joined by fusomes and are dividing synchronously. The origin of the 8-cell clusters in the adult germarium is therefore during larval stages. On emergence, the queen ovary has terminal filaments and germaria but has not yet developed any vitellaria, which are produced after the queen embarks on a nuptial flight. The lack of germaria, and the storing of germline progenitors as clusters, may be adaptions for queen bees to endure the metabolic demands of a nuptial flight, as well as rapidly lay large numbers of eggs to establish a hive.
Assuntos
Células Germinativas , Larva , Ovário , Animais , Abelhas/fisiologia , Ovário/citologia , Feminino , Células Germinativas/citologia , Células Germinativas/metabolismo , Larva/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento , Células-Tronco/citologia , Células-Tronco/metabolismoRESUMO
Vitamin B12 is an essential nutritional co-factor for the folate and methionine cycles, which together constitute one-carbon metabolism. Here, we show that dietary uptake of vitamin B12 modulates cell fate decisions controlled by the conserved RAS/MAPK signaling pathway in C. elegans. A bacterial diet rich in vitamin B12 increases vulval induction, germ cell apoptosis and oocyte differentiation. These effects are mediated by different one-carbon metabolites in a tissue-specific manner. Vitamin B12 enhances via the choline/phosphatidylcholine metabolism vulval induction by down-regulating fat biosynthesis genes and increasing H3K4 tri-methylation, which results in increased expression of RAS/MAPK target genes. Furthermore, the nucleoside metabolism and H3K4 tri-methylation positively regulate germ cell apoptosis and oocyte production. Using mammalian cells carrying different activated KRAS and BRAF alleles, we show that the effects of methionine on RAS/MAPK-regulated phenotype are conserved in mammals. Our findings suggest that the vitamin B12-dependent one-carbon metabolism is a limiting factor for diverse RAS/MAPK-induced cellular responses.
Assuntos
Apoptose , Caenorhabditis elegans , Diferenciação Celular , Metionina , Vitamina B 12 , Animais , Vitamina B 12/metabolismo , Vitamina B 12/farmacologia , Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/genética , Feminino , Metionina/metabolismo , Apoptose/efeitos dos fármacos , Oócitos/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas ras/metabolismo , Carbono/metabolismo , Vulva/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Células Germinativas/metabolismo , Colina/metabolismo , Fosfatidilcolinas/metabolismo , Camundongos , Humanos , Histonas/metabolismo , Transdução de SinaisRESUMO
Most RNA-protein condensates are composed of heterogeneous immiscible phases. However, how this multiphase organization contributes to their biological functions remains largely unexplored. Drosophila germ granules, a class of RNA-protein condensates, are the site of mRNA storage and translational activation. Here, using super-resolution microscopy and single-molecule imaging approaches, we show that germ granules have a biphasic organization and that translation occurs in the outer phase and at the surface of the granules. The localization, directionality, and compaction of mRNAs within the granule depend on their translation status, translated mRNAs being enriched in the outer phase with their 5'end oriented towards the surface. Translation is strongly reduced when germ granule biphasic organization is lost. These findings reveal the intimate links between the architecture of RNA-protein condensates and the organization of their different functions, highlighting the functional compartmentalization of these condensates.
Assuntos
Grânulos Citoplasmáticos , Proteínas de Drosophila , Drosophila melanogaster , Biossíntese de Proteínas , RNA Mensageiro , Animais , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genética , Grânulos Citoplasmáticos/metabolismo , Drosophila melanogaster/metabolismo , Drosophila melanogaster/genética , RNA Mensageiro/metabolismo , RNA Mensageiro/genética , Células Germinativas/metabolismo , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Imagem Individual de Molécula , Drosophila/metabolismo , Drosophila/genética , Condensados Biomoleculares/metabolismoRESUMO
Primordial germ cells (PGCs) are vital for producing sperm and eggs and are crucial for conserving chicken germplasm and creating genetically modified chickens. However, efforts to use PGCs for preserving native chicken germplasm and genetic modification via CRISPR/Cas9 are limited. Here we show that we established 289 PGC lines from eight Chinese chicken populations with an 81.6% success rate. We regenerated Piao chickens by repropagating cryopreserved PGCs and transplanting them into recipient chickens, achieving a 12.7% efficiency rate. These regenerated chickens carried mitochondrial DNA from female donor PGC and the rumplessness mutation from both male and female donors. Additionally, we created the TYRP1 (tyrosinase-related protein 1) knockout (KO) PGC lines via CRISPR/Cas9. Transplanting KO cells into male recipients and mating them with wild-type hens produced four TYRP1 KO chickens with brown plumage due to reduced eumelanin production. Our work demonstrates efficient PGC culture, cryopreservation, regeneration, and gene editing in chickens.
Assuntos
Sistemas CRISPR-Cas , Galinhas , Criopreservação , Células Germinativas , Animais , Galinhas/genética , Células Germinativas/metabolismo , Feminino , Masculino , Oxirredutases/genética , Oxirredutases/metabolismo , Edição de Genes/métodos , Regeneração/genética , Animais Geneticamente Modificados , Quimera/genética , Técnicas de Inativação de GenesRESUMO
Expression of the double homeobox 4 (DUX4) transcription factor is highly regulated in early embryogenesis and is subsequently epigenetically silenced. Ectopic expression of DUX4 due to hypomethylation of the D4Z4 repeat array on permissive chromosome 4q35 alleles is associated with facioscapulohumeral muscular dystrophy (FSHD). In peripheral blood samples from 188 healthy individuals, D4Z4 methylation was highly variable, ranging from 19% to 76%, and was not affected by age. In 48 FSHD2 patients, D4Z4 methylation varied from 3% to 30%. Given that DUX4 is one of the earliest transcribed genes after fertilization, the D4Z4 array is expected to be unmethylated in mature germ cells. Deep bisulfite sequencing of 188 mainly normozoospermic sperm samples revealed an average methylation of 2.5% (range 0.3-22%). Overall, the vast majority (78%) of individual sperm cells displayed no methylation at all. In contrast, only 19 (17.5%) of 109 individual germinal vesicle (GV) oocytes displayed D4Z4 methylation <2.5%. However, it is not unexpected that immature GV oocytes which are not usable for assisted reproduction are endowed with D4Z4 (up to 74%) hypermethylation and/or abnormal (PEG3 and GTL2) imprints. Although not significant, it is interesting to note that the pregnancy rate after assisted reproduction was higher for donors of sperm samples and oocytes with <2.5% methylation.
Assuntos
Metilação de DNA , Células Germinativas , Espermatozoides , Humanos , Metilação de DNA/genética , Masculino , Espermatozoides/metabolismo , Feminino , Células Germinativas/metabolismo , Adulto , Proteínas de Homeodomínio/metabolismo , Proteínas de Homeodomínio/genética , Oócitos/metabolismo , Distrofia Muscular Facioescapuloumeral/genética , Distrofia Muscular Facioescapuloumeral/metabolismo , Distrofia Muscular Facioescapuloumeral/patologia , Pessoa de Meia-IdadeRESUMO
Primordial germ cells (PGCs) in avian species exhibit unique developmental features, including the ability to migrate through the bloodstream and colonize the gonads, allowing their isolation at various developmental stages. Several methods have been developed for the isolation of avian PGCs, including density gradient centrifugation, size-dependent separation, and magnetic-activated cell sorting (MACS) or fluorescence-activated cell sorting (FACS) using a stage-specific embryonic antigen-1 (SSEA-1) antibody. However, these methods present limitations in terms of efficiency and applicability across development stages. In particular, the specificity of SSEA-1 decreases in later developmental stages. Furthermore, surface markers that can be utilized for isolating or utilizing PGCs are lacking for wild birds, including zebra finches, and endangered avian species. To address this, we used single-cell RNA sequencing (scRNA-seq) to uncover novel PGC-specific surface markers in chicken and zebra finch. We screened for genes that were primarily expressed in the PGC population within the gonadal cells. Analyses of gene expression patterns and levels based on scRNA-seq, coupled with validation by RT-PCR, identified NEGR1 and SLC34A2 as novel PGC-specific surface markers in chickens and ESYT3 in zebra finches. Notably, these newly identified genes exhibited sustained expression not only during later developmental stages but also in reproductive tissues.
Assuntos
Galinhas , Tentilhões , Células Germinativas , Análise de Célula Única , Animais , Tentilhões/genética , Análise de Célula Única/métodos , Células Germinativas/metabolismo , Células Germinativas/citologia , Galinhas/genética , Biomarcadores/metabolismo , Análise de Sequência de RNA/métodos , Regulação da Expressão Gênica no Desenvolvimento , MasculinoRESUMO
In mammals, DNA methylation (DNAme) erasure and reinstatement during embryo development and germline establishment are sensitive to the intrauterine environment. Maternal intake of a high-fat diet (HFD), associated with excessive gestational weight gain, has transgenerational effects on offspring health, which may be mediated by changes in DNAme in the germline. Here, we tested the impact of a maternal HFD on embryonic germline DNAme erasure using a rat strain that expresses green fluorescent protein specifically in germ cells. DNAme was analysed by methyl-seq capture in germ cells collected from male and female F1 gonads at gestational day 16. Our data show that although HFD induced global hypomethylation in both sexes, DNAme erasure in female germ cells was more advanced compared to male germ cells. The delay in DNAme erasure in males and the greater impact of HFD suggest that male germ cells are more vulnerable to alterations by exogenous factors.
Assuntos
Metilação de DNA , Dieta Hiperlipídica , Células Germinativas , Animais , Feminino , Dieta Hiperlipídica/efeitos adversos , Masculino , Ratos , Gravidez , Células Germinativas/efeitos dos fármacos , Células Germinativas/metabolismo , Efeitos Tardios da Exposição Pré-Natal/metabolismoRESUMO
Cultured mammalian spermatogonial stem cells (SSCs), also known as germline stem cells (GSCs), hold great promise for applications such as fertility preservation, gene therapy, and animal breeding, particularly in conjunction with accurate gene editing. Although the in vitro development of mouse GSC (mGSC) lines, and gene-targeting procedures for such lines, were initially established about two decades ago, it remains challenging for beginners to efficiently accomplish these tasks, partly because mGSCs proliferate more slowly and are more resistant to lipid-mediated gene transfection than pluripotent stem cells (PSCs). Meanwhile, methods for mGSC culture and gene editing have been evolving constantly to become simpler and more efficient. Here, we describe how to develop mGSC lines from small mouse testis samples and how to carry out gene knock-in in these cells using CRISPR/Cas9 technology, detailing three basic protocols that constitute a streamlined procedure. Using these simple and efficient procedures, site-specific knock-in mGSC lines can be obtained in 3 months. We hope that these protocols will help researchers use genetically modified GSCs to explore scientific questions of interest and to accumulate experience for application to GSC research in other mammalian species. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Establishment of mouse GSCs lines from small testicular samples Basic Protocol 2: Preparation of plasmids for gene knock-in using the CRISPR/Cas9 system Basic Protocol 3: Establishment of gene knock-in mGSC lines by electroporation gene delivery.
Assuntos
Sistemas CRISPR-Cas , Técnicas de Introdução de Genes , Animais , Sistemas CRISPR-Cas/genética , Camundongos , Masculino , Técnicas de Introdução de Genes/métodos , Linhagem Celular , Testículo/citologia , Testículo/metabolismo , Edição de Genes/métodos , Técnicas de Cultura de Células/métodos , Células-Tronco Germinativas Adultas/metabolismo , Células Germinativas/metabolismo , Células Germinativas/citologiaRESUMO
Primordial germ cells (PGCs) are the precursors of gametes and the sole mechanism by which animals transmit genetic information across generations. In the mouse embryo, the transcriptional and epigenetic regulation of PGC specification has been extensively characterized. However, the initial event that triggers the soma-germline segregation remains poorly understood. Here, we uncover a critical role for the basement membrane in regulating germline entry. We show that PGCs arise in a region of the mouse embryo that lacks contact with the basement membrane, and the addition of exogenous extracellular matrix (ECM) inhibits both PGC and PGC-like cell (PGCLC) specification in mouse embryos and stem cell models, respectively. Mechanistically, we demonstrate that the engagement of ß1 integrin with laminin blocks PGCLC specification by preventing the Wnt signaling-dependent down-regulation of the PGC transcriptional repressor, Otx2. In this way, the physical segregation of cells away from the basement membrane acts as a morphogenetic fate switch that controls the soma-germline bifurcation.
Assuntos
Células Germinativas , Células-Tronco Pluripotentes , Animais , Camundongos , Células Germinativas/metabolismo , Células Germinativas/citologia , Células-Tronco Pluripotentes/metabolismo , Células-Tronco Pluripotentes/citologia , Transdução de Sinais , Integrinas/metabolismo , Integrinas/genética , Membrana Basal/metabolismo , Via de Sinalização Wnt , Diferenciação Celular , Matriz Extracelular/metabolismo , Laminina/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Integrina beta1/metabolismo , Integrina beta1/genética , Fatores de Transcrição Otx/metabolismo , Fatores de Transcrição Otx/genética , Embrião de Mamíferos/metabolismo , Embrião de Mamíferos/citologiaRESUMO
Our understanding of the molecular pathways that regulate oogenesis and define cellular identity in the Arthropod female reproductive system and the extent of their conservation is currently very limited. This is due to the focus on model systems, including Drosophila and Daphnia, which do not reflect the observed diversity of morphologies, reproductive modes, and sex chromosome systems. We use single-nucleus RNA and ATAC sequencing to produce a comprehensive single nucleus atlas of the adult Artemia franciscana female reproductive system. We map our data to the Fly Cell Atlas single-nucleus dataset of the Drosophila melanogaster ovary, shedding light on the conserved regulatory programs between the two distantly related Arthropod species. We identify the major cell types known to be present in the Artemia ovary, including germ cells, follicle cells, and ovarian muscle cells. Additionally, we use the germ cells to explore gene regulation and expression of the Z chromosome during meiosis, highlighting its unique regulatory dynamics and allowing us to explore the presence of meiotic sex chromosome silencing in this group.
Assuntos
Artemia , Drosophila melanogaster , Células Germinativas , Meiose , Oogênese , Ovário , Cromossomos Sexuais , Animais , Feminino , Cromossomos Sexuais/genética , Células Germinativas/metabolismo , Artemia/genética , Meiose/genética , Ovário/metabolismo , Oogênese/genética , Drosophila melanogaster/genética , Núcleo Celular/genética , Reprodução/genéticaRESUMO
The chromosome segregation and cell division programs associated with somatic mitosis and germline meiosis display dramatic differences such as kinetochore orientation, cohesin removal, or the presence of a gap phase.1,2,3,4,5,6 These changes in chromosome segregation require alterations to the established cell division machinery.5,6 It remains unclear what aspects of kinetochore function and its regulatory control differ between the mitotic and meiotic cell divisions to rewire these core processes. Alternative RNA splicing can generate distinct protein isoforms to allow for the differential control of cell processes across cell types. However, alternative splice isoforms that differentially modulate distinct cell division programs have remained elusive. Here, we demonstrate that mammalian germ cells express an alternative mRNA splice isoform for the kinetochore component, DSN1, a subunit of the MIS12 complex that links the centromeres to spindle microtubules during chromosome segregation. This germline DSN1 isoform bypasses the requirement for Aurora kinase phosphorylation for its centromere localization due to the absence of a key regulatory region allowing DSN1 to display persistent centromere localization. Expression of the germline DSN1 isoform in somatic cells results in constitutive kinetochore localization, chromosome segregation errors, and growth defects, providing an explanation for its tight cell-type-specific expression. Reciprocally, precisely eliminating expression of the germline-specific DSN1 splice isoform in mouse models disrupts oocyte maturation and early embryonic divisions coupled with a reduction in fertility. Together, this work identifies a germline-specific splice isoform for a chromosome segregation component and implicates its role in mammalian fertility.
Assuntos
Processamento Alternativo , Segregação de Cromossomos , Desenvolvimento Embrionário , Oócitos , Isoformas de Proteínas , Animais , Oócitos/metabolismo , Camundongos , Feminino , Desenvolvimento Embrionário/genética , Isoformas de Proteínas/metabolismo , Isoformas de Proteínas/genética , Cinetocoros/metabolismo , Células Germinativas/metabolismo , MasculinoRESUMO
In animals, stem cell populations of varying potency facilitate regeneration and tissue homeostasis. Notably, germline stem cells in both vertebrates and invertebrates express highly conserved RNA binding proteins, such as nanos, vasa, and piwi. In highly regenerative animals, these genes are also expressed in somatic stem cells, which led to the proposal that they had an ancestral role in all stem cells. In cnidarians, multi- and pluripotent interstitial stem cells have only been identified in hydrozoans. Therefore, it is currently unclear if cnidarian stem cell systems share a common evolutionary origin. We, therefore, aimed to characterize conserved stem cell marker genes in the sea anemone Nematostella vectensis. Through transgenic reporter genes and single-cell transcriptomics, we identify cell populations expressing the germline-associated markers piwi1 and nanos2 in the soma and germline, and gene knockout shows that Nanos2 is indispensable for germline formation. This suggests that nanos and piwi genes have a conserved role in somatic and germline stem cells in cnidarians.
Assuntos
Células Germinativas , Proteínas de Ligação a RNA , Anêmonas-do-Mar , Animais , Anêmonas-do-Mar/genética , Anêmonas-do-Mar/metabolismo , Células Germinativas/metabolismo , Células Germinativas/citologia , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Linhagem da Célula/genética , Células-Tronco/metabolismo , Células-Tronco/citologia , Proteínas Argonautas/metabolismo , Proteínas Argonautas/genéticaRESUMO
Fertility requires the faithful proliferation of germ cells and their differentiation into gametes. Controlling these cellular states demands precise timing and expression of gene networks. Nucleic acid binding proteins (NBPs) play critical roles in gene expression networks that influence germ cell development. There has, however, been no functional analysis of the entire NBP repertoire in controlling in vivo germ cell development. Here, we analyzed germ cell states and germline architecture to systematically investigate the function of 364 germline-expressed NBPs in the Caenorhabditis elegans germ line. Using germline-specific knockdown, automated germ cell counting, and high-content analysis of germ cell nuclei and plasma membrane organization, we identify 156 NBPs with discrete autonomous germline functions. By identifying NBPs that control the germ cell cycle, proliferation, differentiation, germline structure and fertility, we have created an atlas for mechanistic dissection of germ cell behavior and gamete production.
Assuntos
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Células Germinativas , Animais , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Células Germinativas/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Regulação da Expressão Gênica no Desenvolvimento , Diferenciação Celular/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Fertilidade/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/genética , Proliferação de Células/genética , Ciclo Celular/genética , Masculino , Redes Reguladoras de GenesRESUMO
The number of infertile couples undergoing in vitro fertilisation (IVF) has increased significantly. The efficacy of this procedure is contingent upon a multitude of factors, including gamete quality. One factor influencing gamete quality is oxidative stress, which leads to telomere damage and accelerates cellular ageing. Identifying new biomarkers that can predict the success of assisted reproduction techniques is a current relevant area of research. In this review, we discuss the potential role of SIRT1, a protein known to protect against oxidative stress and telomeres, which are responsible for genome stability, as biomarkers of gamete quality and assisted reproduction technique outcomes.
Assuntos
Biomarcadores , Fertilização in vitro , Estresse Oxidativo , Sirtuína 1 , Telômero , Humanos , Fertilização in vitro/métodos , Telômero/metabolismo , Telômero/genética , Sirtuína 1/metabolismo , Sirtuína 1/genética , Células Germinativas/metabolismo , Fertilidade/genética , Feminino , MasculinoRESUMO
Germline stem cells are a crucial type of stem cell that can stably pass on genetic information to the next generation, providing the necessary foundation for the reproduction and survival of organisms. Male mammalian germline stem cells are unique cell types that include primordial germ cells and spermatogonial stem cells. They can differentiate into germ cells, such as sperm and eggs, thereby facilitating offspring reproduction. In addition, they continuously generate stem cells through self-renewal mechanisms to support the normal function of the reproductive system. Autophagy involves the use of lysosomes to degrade proteins and organelles that are regulated by relevant genes. This process plays an important role in maintaining the homeostasis of germline stem cells and the synthesis, degradation, and recycling of germline stem cell products. Recently, the developmental regulatory mechanism of germline stem cells has been further elucidated, and autophagy has been shown to be involved in the regulation of self-renewal and differentiation of germline stem cells. In this review, we introduce autophagy accompanying the development of germline stem cells, focusing on the autophagy process accompanying the development of male spermatogonial stem cells and the roles of related genes and proteins. We also briefly outline the effects of autophagy dysfunction on germline stem cells and reproduction.
Assuntos
Autofagia , Células-Tronco , Autofagia/fisiologia , Masculino , Animais , Humanos , Células-Tronco/citologia , Células-Tronco/metabolismo , Células Germinativas/citologia , Células Germinativas/metabolismo , Diferenciação CelularRESUMO
Sex determination in animals is not only determined by karyotype but can also be modulated by environmental cues like temperature via unclear transduction mechanisms. Moreover, in contrast to earlier views that sex may exclusively be determined by either karyotype or temperature, recent observations suggest that these factors rather co-regulate sex, posing another mechanistic mystery. Here, we discovered that certain wild-isolated and mutant C. elegans strains displayed genotypic germline sex determination (GGSD), but with a temperature-override mechanism. Further, we found that BiP, an ER chaperone, transduces temperature information into a germline sex-governing signal, thereby enabling the coexistence of GGSD and temperature-dependent germline sex determination (TGSD). At the molecular level, increased ER protein-folding requirements upon increased temperatures lead to BiP sequestration, resulting in ERAD-dependent degradation of the oocyte fate-driving factor, TRA-2, thus promoting male germline fate. Remarkably, experimentally manipulating BiP or TRA-2 expression allows to switch between GGSD and TGSD. Physiologically, TGSD allows C. elegans hermaphrodites to maintain brood size at warmer temperatures. Moreover, BiP can also influence germline sex determination in a different, non-hermaphroditic nematode species. Collectively, our findings identify thermosensitive BiP as a conserved temperature sensor in TGSD, and provide mechanistic insights into the transition between GGSD and TGSD.
Assuntos
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Células Germinativas , Processos de Determinação Sexual , Temperatura , Animais , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Masculino , Células Germinativas/metabolismo , Feminino , Proteínas de Choque Térmico/metabolismo , Proteínas de Choque Térmico/genéticaRESUMO
Stem cells often rely on signals from a niche, which in many tissues adopts a precise morphology. What remains elusive is how niches are formed and how morphology impacts function. To address this, we leverage the Drosophila gonadal niche, which affords genetic tractability and live-imaging. We have previously shown mechanisms dictating niche cell migration to their appropriate position within the gonad and the resultant consequences on niche function. Here, we show that once positioned, niche cells robustly polarize filamentous actin (F-actin) and non-muscle myosin II (MyoII) toward neighboring germ cells. Actomyosin tension along the niche periphery generates a highly reproducible smoothened contour. Without contractility, niches are misshapen and exhibit defects in their ability to regulate germline stem cell behavior. We additionally show that germ cells aid in polarizing MyoII within niche cells and that extrinsic input is required for niche morphogenesis and function. Our work reveals a feedback mechanism where stem cells shape the niche that guides their behavior.
Assuntos
Actomiosina , Drosophila melanogaster , Nicho de Células-Tronco , Células-Tronco , Animais , Actomiosina/metabolismo , Nicho de Células-Tronco/fisiologia , Células-Tronco/fisiologia , Células-Tronco/metabolismo , Células-Tronco/citologia , Drosophila melanogaster/fisiologia , Miosina Tipo II/metabolismo , Células Germinativas/fisiologia , Células Germinativas/metabolismo , Masculino , Movimento Celular , Drosophila/fisiologia , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genéticaRESUMO
The Caenorhabditis elegans germline is arranged spatiotemporally and is therefore a powerful model system for the interrogation of meiotic molecular dynamics. Coupling this property with the temporal control that the auxin-inducible degron (AID) system allows can unveil new/unappreciated roles for critical meiotic factors in specific germline regions. Here we describe a widely used approach for the introduction of degron tags to specific targets and provide a procedure for applying the AID system to C. elegans meiotic DSB repair dynamics in the germline.