TY - JOUR. T1 - Proliferation of mouse primordial germ cells in Vitro. T2 - A key role for cAMP. AU - De Felici, Massimo. AU - Dolci, Susanna. AU - Pesce, Maurizio. PY - 1993. Y1 - 1993. N2 - Two agents known to enhance the level of intracellular cAMP (dibutyryl cAMP and forskolin) markedly increase the number of 8.5, 10.5, and 11.5 days postcoitum (dpc) mouse primordial germ cells (PGCs) cultured on TM4 cell feeder layers. Forskolin (FRSK) caused a significant increase of PGC number also in monodispersed cell suspensions obtained from PGC-containing tissues of the three embryonic ages studied and in purified 11.5 dpc PGCs cultured without feeder layers. The addition to the culture medium of adenosine-3′,5′-cyclic monophosphorothioate RP isomer (Rp-cAMPS, a competitive antagonist for cAMP-dependent protein kinases), significantly reduced the effects of FRSK. Last, FRSK stimulated PGC proliferation, as assessed by 5-bromo-2′-deoxyuridin incorporation. We conclude that cAMP-dependent ...
In Drosophila, the posterior determinant nanos is required for embryonic patterning and for primordial germ cell (PGC) development. We have identified three genes in Caenorhabditis elegans that contain a putative zinc-binding domain similar to the one found in nanos, and show that two of these genes function during PGC development. Like Drosophila nanos, C. elegans nos-1 and nos-2 are not generally required for PGC fate specification, but instead regulate specific aspects of PGC development. nos-2 is expressed in PGCs around the time of gastrulation from a maternal RNA associated with P granules, and is required for the efficient incorporation of PGCs into the somatic gonad. nos-1 is expressed in PGCs after gastrulation, and is required redundantly with nos-2 to prevent PGCs from dividing in starved animals and to maintain germ cell viability during larval development. In the absence of nos-1 and nos-2, germ cells cease proliferation at the end of the second larval stage, and die in a manner ...
Jenn-Fa Liou, Yu-Min Shue, Hsiao-Lung Liu, Chein Tai, Lih-Ren Chen, and Jen-Wen Shiau. The objective of this study was to evaluate the capacity of gonadal migration and characterization for chicken primordial germ cells (PGCs) after long-term in vitro culture. Chicken PGCs collected from the primitive gonads of 5.5-day-old White Leghorn chicken embryos were plated together with their own stroma cells as co-culture. The cultured PGCs began to from colonies 7-10 days after plating. The PGC-derived colonies maintained in culture up to 280 days were positively stained with antibodies specific to SSEA-1, SSEA-4, integrin α6 and integrin β1, and also strongly expressed periodic acid Schiff reaction. Their capacities of migration and colonizing in the primary gonadal ridge were further demonstrated by transferring to stage 14-15 (3 days old) recipient embryos. These results suggested that chicken PGCs maintained in long-term culture retains their capacity to express pluripotent markers and to ...
Liu-Xiao-Ping; Gao-Ying-Mao; Xu-Luo; Guo-Fei-Fei; Bing-Lu-Jun, 2007: The effect of transplantation of mouse primordial germ cells on the acute damaged liver
The directional migration and the following development of primordial germ cells (PGCs) during gonad formation are key steps for germline development. It has been proposed that the interaction between germ cells and genital ridge (GR) somatic cells plays essential roles in this process. However, the in vivo functional requirements of GR somatic cells in germ cell development are largely unknown. Wt1 mutation (Wt1R394W/R394W) results in GR agenesis through mitotic arrest of coelomic epitheliums. In this study, we employed the GR-deficient mouse model, Wt1R394W/R394W, to investigate the roles of GR somatic cells in PGC migration and proliferation. We found that the number of PGCs was dramatically reduced in GR-deficient embryos at embryonic day (E) 11.5 and E12.5 due to decreased proliferation of PGCs, involving low levels of BMP signaling. In contrast, the germ cells in Wt1R394W/R394W embryos were still mitotically active at E13.5, while all the germ cells in control embryos underwent mitotic arrest at
Although mutations are the force of evolution, most mutations are deleterious. Faithful inheritance of genetic information is the key to evolutionary success. The only cell lineage that is capable of transferring genetic information is the germ line. Therefore, refined control of mutation frequency in germ cells is of great importance. The control mechanism mainly involves the DNA damage response (DDR), since DNA damage is the major source of mutations. In mammals, most studies on germ line mutation and DDR focus on meiosis. In contrast, little is known about these processes in primordial germ cells (PGCs). In particular, checkpoint signaling has not been characterized in PGCs. Multiple analysis showed that the mutation rate in germ cells is consistently lower than that in somatic cells. Therefore, it has been proposed that there is a fundamental difference in DDR between germ cells and somatic cells. Indeed, a few DDR mutants have revealed a hypersensitivity of PGCs to DNA damage. In this ...
Directional cell migration is an intensively studied process relevant for both normal development of an organism as well as for a number of pathological conditions such as chronic inflammation and cancer. Primordial germ cells (PGCs) in Xenopus laevis embryos can be used as a model system to study cell migration, since during embryogenesis they actively migrate within the endoderm towards genital ridges. Transition to active cell migration is a highly regulated process important for the normal PGC development in many species. This study is focused on molecular and cellular mechanisms involved in initiation of active PGC migration within the endoderm of X. laevis embryos. Analysis of cell shape fluctuations demonstrated that in comparison to pre-migratory neural stage, PGCs isolated from tailbud stage embryos are characterized by an increased cellular dynamics due to formation of bleb-like protrusions and migration via bleb-associated mechanism. Analysis of intracellular PIP3 distribution that ...
Epigenetic reprogramming in mammalian germ cells, zygote and early embryos, plays a crucial role in regulating genome functions at critical stages of development. Germ line epigenetic reprogramming assures erasure of all the imprinting marks and epi-mutations and establishment of new sex-specific gametic imprints. The presented work focuses on the erasure of epigenetic modifications that occur in mouse primordial germ cells (PGCs) between day 10.5 to 13.5 post coitum (dpc). Contrary to previous assumptions, our results show that as they enter the genital ridge the PGCs still possess DNA methylation marks comparable to those found in somatic cells. Shortly after the entry of PGCs into the gonadal anlagen the DNA methylation marks associated with imprinted and non-imprinted genes are erased. For most genes the erasure commences simultaneously in PGCs of both male and female embryos and is completed within only one day of development. The kinetics of this process indicates that is an active ...
Stochastic specification of primordial germ cells from mesoderm precursors in axolotl embryos[7] "A common feature of development in most vertebrate models is the early segregation of the germ line from the soma. For example, in Xenopus and zebrafish embryos primordial germ cells (PGCs) are specified by germ plasm that is inherited from the egg; in mice, Blimp1 expression in the epiblast mediates the commitment of cells to the germ line. How these disparate mechanisms of PGC specification evolved is unknown. Here, in order to identify the ancestral mechanism of PGC specification in vertebrates, we studied PGC specification in embryos from the axolotl (Mexican salamander), a model for the tetrapod ancestor. In the axolotl, PGCs develop within mesoderm, and classic studies have reported their induction from primitive ectoderm (animal cap). We used an axolotl animal cap system to demonstrate that signalling through FGF and BMP4 induces PGCs. The role of FGF was then confirmed in vivo. We also ...
Stem cells in adult animal tissues have the ability to self-renew and differentiate into functional cells that replenish lost cells. Their self-renewal and differentiation are controlled by concerted actions of extrinsic factors and intrinsic factors (1, 2). Although a plethora of intrinsic factors has been identified for their roles in stem cell regulation, it remains largely unclear how differentiation factors are functionally repressed in stem cells. In this study, we show that a translation initiation factor eIF4A maintains germline stem cell (GSC) self-renewal in the Drosophila ovary by antagonizing the differentiation factor BAM.. In the Drosophila ovary, 2 or 3 GSCs are located at the tip of the germarium, where they are directly anchored to cap cells through E-cadherin-mediated cell adhesion (3). In addition, GSCs are also laterally wrapped around by escort stem cells (4). After GSC division, the daughter attaching to cap cells/escort stem cells renews as a stem cell, while the other ...
As with cultures of mouse ES cells, human ES cells begin to differentiate if they are removed from feeder layers and grown in suspension culture on a non-adherent surface. The human ES cells form embryoid bodies which, in the early stages, may be simple or cystic and filled with fluid. Although human embryoid bodies vary in their cellular content, many include cells that look like neurons and heart muscle cells [14, 25, 26].. After the human embryoid bodies form, they can be dissociated and replated in monolayer cultures which are then exposed to specific growth factors that influence further cell differentiation. Some growth factors induce cell types that would normally be derived from ectoderm in the embryo; these include retinoic acid, epidermal growth factor (EGF), bone morphogenic protein 4 (BMP4), and basic fibroblast growth factor (bFGF). Other growth factors, such as activin-A and transforming growth factor-beta 1 (TGF-ß1) trigger the differentiation of mesodermally derived cells. Two ...
Germ cell development is a step-wise process that ensures the progression of the life cycle due to their unique ability to transmit their genome from one generation to the next. In the mouse, the precursors of germ cells, the Primordial Germ Cells (PGCs), arise at the onset of gastrulation. Here we discuss how PGCs acquire their fate in the epiblast and outline their development until their arrival into the gonads. Male germ cell tumors (GCTs) have a similar gene expression pattern to that of fetal germ cells and to pluripotent cells, suggesting that GCT originate from an alteration of gonocyte normal development. We evaluate coincidences and differences in germ cell development in mouse and humans and on this basis, we speculate future research perspectives.
We have developed a technology to efficiently produce infertile fish by disrupting primordial germ cell development in fish embryos. The technology uses a bath immersion to administer a Morpholino oligomer (MO) against Deadend (Dnd), an essential protein for early germ cell development in fish. This approach has been successfully used in the zebrafish, trout and salmon. The goal of this proposal is to examine the feasibility of applying this technology to sablefish. ...
We have developed a technology to efficiently produce infertile fish by disrupting primordial germ cell development in fish embryos. The technology uses a bath immersion to administer a Morpholino oligomer (MO) against Deadend (Dnd), an essential protein for early germ cell development in fish. This approach has been successfully used in the zebrafish, trout and salmon. The goal of this proposal is to examine the feasibility of applying this technology to sablefish. ...
Background Dmrt1 is a highly conserved gene involved in the determination and early differentiation phase of the primordial gonad in vertebrates. In the fish medaka dmrt1bY, a functional duplicate of...
Germ cell sex is defined by factors derived from somatic cells. CYP26B1 is known to be a male sex-promoting factor that inactivates retinoic acid (RA) in somatic cells. In CYP26B1-null XY gonads, germ cells are exposed to a higher level of RA than in normal XY gonads and this activates Stra8 to induce meiosis while male-specific gene expression is suppressed. However, it is unknown whether meiotic entry by an elevated level of RA is responsible for the suppression of male-type gene expression. To address this question, we have generated Cyp26b1/Stra8 double knockout (dKO) embryos. We successfully suppressed the induction of meiosis in CYP26B1-null XY germ cells by removing the Stra8 gene. Concomitantly, we found that the male genetic program represented by the expression of NANOS2 and DNMT3L was totally rescued in about half of dKO germ cells, indicating that meiotic entry causes the suppression of male differentiation. However, half of the germ cells still failed to enter the appropriate male pathway
The homeostasis of self-renewal and differentiation in stem cells is strictly controlled by intrinsic signals and their niche. We conducted a large-scale RNA interference (RNAi) screen in Drosophila testes and identified 221 genes required for germline stem cell (GSC) maintenance or differentiation. Knockdown of these genes in transit-amplifying spermatogonia and cyst cells further revealed various phenotypes. Complex analysis uncovered that many of the identified genes are involved in key steps of protein synthesis and degradation. A group of genes that are required for mRNA splicing and protein translation contributes to both GSC self-renewal and early germ cell differentiation. Loss of genes in protein degradation pathway in cyst cells leads to testis tumor with overproliferated germ cells. Importantly, in the Cullin 4-Ring E3 ubiquitin ligase (CRL4) complex, we identified multiple proteins that are critical to GSC self-renewal. pic/DDB1, the linker protein of CRL4, is not only required for ...
Background The regulation of gene expression via a 3′ untranslated region (UTR) plays essential roles in the discrimination of the germ cell lineage from somatic cells during embryogenesis. This is fundamental to the continuation of a species. Mouse NANOS3 is an essential protein required for the germ cell maintenance and is specifically expressed in these cells. However, the regulatory mechanisms that restrict the expression of this gene in the germ cells is largely unknown at present. Methodology/Principal Findings In our current study, we show that differences in the stability of Nanos3 mRNA between germ cells and somatic cells is brought about in a 3′UTR-dependent manner in mouse embryos. Although Nanos3 is transcribed in both cell lineages, it is efficiently translated only in the germ lineage. We also find that the translational suppression of NANOS3 in somatic cells is caused by a 3′UTR-mediated mRNA destabilizing mechanism. Surprisingly, even when under the control of the CAG promoter
Witschi E. Rat Development. In: Growth Including Reproduction and Morphological Development. (1962) Altman PL. and Dittmer DS. ed. Fed. Am. Soc. Exp. Biol., Washington DC, pp. 304-314 ...
Clusters of primordial germ cells (PGCs) with somatic cells come closer to form ovigerous cords, which is first discernible in the fetal ovary upon establishment of initial contact between germ cells and somatic cells near the surface of the ovarian epithelium.. The first mechanistic difference between an XX and an XY germ cell in the genital ridge is reactivation of the inactive X in the female PGCs. The XX germ cells continue to divide and then enter meiosis at around E12.5. Subsequently, the female germ cells arrest at the diplotene stage of meiosis I and do not resume meiosis until postnatal ovarian folliculogenesis.. Folliculogenesis: Before formation of an ovarian follicle, oocytes are present within germ cell clusters (cysts or nests). The first stage of ovarian folliculogenesis involves the formation of the primordial follicle, which occurs when oocytes that survive the process of germ cell cluster breakdown are individually surrounded with squamous pre-granulosa cells. This takes place ...
Nanos is expressed in multipotent cells, stem cells, and primordial germ cells (PGCs) of organisms as diverse as jellyfish and humans. It functions together with Pumilio to translationally repress targeted mRNAs. Here we show by loss-of-function experiments that Xenopus Nanos1 is required to preserve PGC fate. Morpholino knockdown of maternal Nanos1 resulted in a striking decrease in PGCs and loss of germ cells from the gonads. Lineage tracing and TUNEL staining reveals that Nanos1 deficient PGCs fail to migrate out of the endoderm. They appear to undergo apoptosis rather than convert to normal endoderm. Whereas normal PGCs do not become transcriptionally active until neurula, Nanos1 depleted PGCs prematurely express a hyperphosphorylated RNA Pol II-CTD at the mid-blastula transition. Furthermore, they now inappropriately express somatic genes characteristic of endoderm regulated by maternal VegT including Xsox17-alpha, Bix4, Mixer, GATA4, and Edd. We further demonstrate that Pumilio specifically
Chromatin epigenetics participate in control of gene expression during metazoan development. DNA methylation and post-translational modifications (PTMs) of histones have been extensively characterised in cell types present in, or derived from, mouse embryos. In embryonic stem cells (ESCs) derived from blastocysts, factors involved in deposition of epigenetic marks regulate properties related to self-renewal and pluripotency. In the germ lineage, changes in histone PTMs and DNA demethylation occur during formation of the primordial germ cells (PGCs) to reset the epigenome of the future gametes. Trimethylation of histone H3 on lysine 27 (H3K27me3) by Polycomb group proteins is involved in several epigenome-remodelling steps, but it remains unclear whether these epigenetic features are conserved in non-mammalian vertebrates. To investigate this question, we compared the abundance and nuclear distribution of the main histone PTMs, 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) in chicken ESCs,
To estimate the developmental toxicity of environmental chemicals on the formation of primordial germ cells (PGCs), Xenopus laevis embryos were exposed to caffeine at 200 mg/l during the migratory stage of presumptive PGCs. The PGC-containing region of the larvae at stage 46, which corresponds to genital ridge, was illuminated by cold light using a halogen lamp and photographed using a digital camera under a dissecting microscope. The length along the cephalocaudal axis and area of the PGC-containing region were measured using image-measuring software. The length and area of the PGC-containing region as well as its relative length compared to the 100-µn;m body length of caffeine-exposed larvae were significantly shorter and smaller, respectively, than those of the control. Though further studies concerning the effect of caffeine on PGC formation are needed, these findings suggest that the Xenopus embryo and larva system examined in this study is useful as a simple, rapid and low-cost ...
TY - JOUR. T1 - zif-1 translational repression defines a second, mutually exclusive OMA function in germline transcriptional repression. AU - Guven-Ozkan, Tugba. AU - Robertson, Scott M.. AU - Nishi, Yuichi. AU - Lin, Rueyling. PY - 2010/10/15. Y1 - 2010/10/15. N2 - Specification of primordial germ cells requires global repression of transcription. In C. elegans, primordial germ cells are generated through four rounds of asymmetric divisions, starting from the zygote P0, each producing a transcriptionally repressed germline blastomere (P1-P4). Repression in P2-P4 requires PIE-1, which is provided maternally in oocytes and segregated to all germline blastomeres. We have shown previously that OMA-1 and OMA-2 repress global transcription in P0 and P1 by sequestering TAF-4, an essential component of TFIID. Soon after the first mitotic cycle, OMA proteins undergo developmentally regulated degradation. Here, we show that OMA proteins also repress transcription in P2-P4 indirectly, through a completely ...
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The Hedgehog (Hh) pathway is activated in follicle stem cells of animals lacking boi (CIL# 13757), relative to wild-type Drosophila (this image), base...
ESRP1 regulates alternative splicing, producing multiple transcripts from its target genes in epithelial tissues. It is upregulated during mesenchymal to epithelial transition associated with reprogramming of fibroblasts to iPS cells and has been linked to pluripotency. Mouse fetal germ cells are the founders of the adult gonadal lineages and we found that Esrp1 mRNA was expressed in both male and female germ cells but not in gonadal somatic cells at various stages of gonadal development (E12.5-E15.5). In the postnatal testis, Esrp1 mRNA was highly expressed in isolated cell preparations enriched for spermatogonia but expressed at lower levels in those enriched for pachytene spermatocytes and round spermatids ...
Germ cells occupy a central position in development, heredity, and evolution. In mammals, germ cells are first recognizable outside the portion of the embryo that will form the body. These primordial germ cells invade the developing body and migrate to the gonads, which at that stage are indistinguishable in males and females. The gonads differentiate into ovaries or testes. In parallel, the primordial germ cells become committed to give rise to oocytes or sperm. We use genetic tools to explore the development of the mammalian reproductive tract. While much of our research has focused on the mechanism by which the ovarian or testicular fate of the embryonic gonad is decided, our studies are increasingly directed toward understanding the mechanisms by which primordial germ cells give rise to gametes.. Germ Cell Development and Male Infertility: Three percent of men are infertile because of severe defects in sperm production. In few cases has the cause of spermatogenic failure been identified. We ...
We focus on the development of a single tissue, the germline, in the model organism C. elegans. This small nematode provides two key advantages: an excellent genetic system for understanding how cell fate is specified, and a completely sequenced and well-annotated genome. We use functional genomics tools to dissect the molecular mechanisms governing germ cell maintenance and differentiation in the model organism C. elegans. Conserved regulatory pathways, such as the Notch, Ras, and Retinoblastoma pathways, act to control proliferation and differentiation in these cells. The developing C. elegans germline requires tight spatial and temporal control of gene activity for proper formation. Epigenetic control of gene expression plays an important role in governing germ cell fate through the post-translational modification of histones and by RNAi-mediated post-transcriptional control. Projects in the lab investigate the mechanisms controlling germ cell specification in the early embryo, as well as the ...
Abortion obviously produces aborted fetuses. The taboo of using aborted fetal tissue for research is not a deterrent for some researchers; such tissue is just another tool in their toolbox. West freely admits that he has used aborted fetal tissue to advance his research. By scrambling around and persuading, I found a means of getting early human fetal testes and tried to grow the human embryonic germ cell in a dish. But, for his research, those germ cells were too old. In his words, I needed five week old fetuses. But where could I get those? Women do not abort fetuses that early, when they are just learning they are pregnant. 9. It is not just testes from aborted male babies that researchers want. Some want eggs from aborted female babies as well. The much-ignored reality of therapeutic cloning is this: to become a viable commercial therapy, an enormous amount of human eggs are required. For every attempt at cloning to harvest embryonic stem cells, it usually requires more than one human egg. ...
Abortion obviously produces aborted fetuses. The taboo of using aborted fetal tissue for research is not a deterrent for some researchers; such tissue is just another tool in their toolbox. West freely admits that he has used aborted fetal tissue to advance his research. By scrambling around and persuading, I found a means of getting early human fetal testes and tried to grow the human embryonic germ cell in a dish. But, for his research, those germ cells were too old. In his words, I needed five week old fetuses. But where could I get those? Women do not abort fetuses that early, when they are just learning they are pregnant. 9. It is not just testes from aborted male babies that researchers want. Some want eggs from aborted female babies as well. The much-ignored reality of therapeutic cloning is this: to become a viable commercial therapy, an enormous amount of human eggs are required. For every attempt at cloning to harvest embryonic stem cells, it usually requires more than one human egg. ...
Background Avian primordial germ cells (PGCs) have significant potential to be utilized as a cell-based system for the research and preservation of bird germplasm, and the hereditary modification of the bird genome. development of ovum and semen in the adult patient. In mammals, PGCs are described at the starting of gastrulation. In comparison, in bird varieties the bacteria cell family tree can be segregated from somatic cell lineages in the epiblast of the placed egg [1]. Early bacteria cell precursors in poultry embryos can become determined by the phrase of the bacteria cell-specific proteins, chicken breast PD173074 vasa homologue (CVH) [2]. From a placement in the central epiblast, PGCs migrate to an extraembryonic area to the potential mind area anterior, called the germinal crescent. From right here, at three times of advancement (stage 15 HH, [3]), the PGCs invade the developing vascular program, congregate in the horizontal dish mesoderm conjoining the potential gonadal area, and ...
Embryo formation requires tight regulation and coordination of adhesion in multiple cell types. By imaging, 3D reconstructions and genetic analysis during posterior midgut morphogenesis in Drosophila we find a novel requirement for the conserved FGF signaling pathway in maintenance of epithelial cell adhesion, by modulation of zygotic E-cadherin. During Drosophila gastrulation, primordial germ cells (PGC) are transported with the posterior midgut while it undergoes dynamic cell shape changes. In Branchless and Breathless mutant embryos zygotic E-cadherin is not targeted to AJs causing midgut pocket collapse impacting on PGC movement. We find that the ventral midline also requires FGF signaling to maintain cell-cell adhesion. We show that FGF signaling regulates the distribution of zygotic E-cadherin during early embryonic development to maintain cell-cell adhesion in the posterior midgut and the ventral midline, a role that is likely crucial in other tissues undergoing active cell shape changes ...
Additionally, Silman et al. identified that there is an abrupt reduction in melatonin amounts amongst boys just prior to a increase in testosterone stages with
We have here reported the generation of a transgenic strain that recapitulates the endogenous expression and subcellular localization of NANOS3, and rescues the germ cell-less phenotype of Nanos3 homozygous−/− mutant mice. Nanos is an evolutionarily conserved RNA-binding protein essential for germ cell development and is a component of germ plasm in organisms, in which germ cells are specified by germ plasm-based preformation (Wang & Lehmann 1991, Subramaniam & Seydoux 1999, Seydoux & Braun 2006). NANOS3 is a mammalian homolog of Nanos, whose function is critical for the survival of PGCs immediately after their specification (Tsuda et al. 2003). However, the mechanism by which NANOS3 functions in PGCs remains totally unresolved. The Nanos3-EGFP transgenic strain, which, for the first time, revealed the precise subcellular localization of NANOS3 in PGCs and spermatogonia, should thus serve as a critical model for exploring the mechanisms of action of conserved RNA-binding proteins in PGCs ...
1998 Thomson et al., derive human ES cells from the inner cell mass of normal human blastocysts donated by couples undergoing treatment for infertility. The cells are cultured through many passages, retain their normal karyotypes, maintain high levels of telomerase activity, and express a panel of markers typical of human EC cells non-human primate ES cells. Several (non-clonal) cell lines are established that form teratomas when injected into immune-deficient mice. The teratomas include cell types derived from all three primary germ layers, demonstrating the pluripotency of human ES cells. Gearhart and colleagues derive human embryonic germ (EG) cells from the gonadal ridge and mesenchyma of 5- to 9-week fetal tissue that resulted from elective abortions. They grow EG cells in vitro for approximately 20 passages, and the cells maintain normal karyotypes. The cells spontaneously form aggregates that differentiate spontaneously, and ultimately contain derivatives of all three primary germ ...
Following primordial germ cell (PGC) specification, global, as well as parent-specific, methylation marks are erased, to be subsequently re-established in a sex-dependent manner during gametogenesis. Identification of key regulators that participate in the global remodeling of the epigenome, together with genome-wide sequencing maps of the dynamic epigenome landscape from the post-implantation embryo through gametogenesis, significantly enhanced our understanding of these key events. Yet, a full understanding of the developmental timing, kinetics and mechanisms of these processes at different loci is still far from complete. Furthermore, as previous studies mostly applied bulk population sequencing approaches, the levels of cell-to-cell variations was not fully appreciated. We will utilize our allele-specific DNA methylation reporter systems to monitor sex-specific methylation erasure and establishment, at single cell resolution. Our unique experimental systems, which allow the monitoring and ...
BackgroundInfertility affects ∼20% of couples in Europe and in 50% of cases the problem lies with the male partner. The impact of damaged DNA originating in the male germ line on infertility is poorly understood but may increase miscarriage. Mouse models allow us to investigate how deficiencies in DNA repair/damage response pathways impact on formation and function of male germ cells. We have investigated mice with deletions of ERCC1 (excision repair cross-complementing gene 1), MSH2 (MutS homolog 2, involved in mismatch repair pathway), and p53 (tumour suppressor gene implicated in elimination of germ cells with DNA damage).Principal FindingsWe demonstrate for the first time that depletion of ERCC1 or p53 from germ cells results in an increased incidence of unrepaired DNA breaks in pachytene spermatocytes and increased numbers of caspase-3 positive (apoptotic) germ cells. Sertoli cell-only tubules were detected in testes from mice lacking expression of ERCC1 or MSH2 but not p53. The number of sperm
Drosophila GSCs have been a long-standing model for studying stem cell division and differentiation. The only necessary and direct inducer of female GSC differentiation is Bam, which has been speculated to act post-transcriptionally. Here, we explore the transcriptional changes occurring as a consequence of absence of Bam using NGS and find almost a third of the known Drosophila genome to be differentially regulated. It is pertinent to point out here that we use the whole germline (vas-GFP+ cells) as a comparative population for calculating relative differential expression. Also, since we use a fluorescence-based sorting strategy, it is conceivable that cells expressing GFP at higher intensities - for instance, larger cells such as nurse cells or eight-cell cysts - would tend to be preferentially sorted. This would dilute the ideal comparative scenario - comparing the transcriptome of a GSC with its direct descendent, the cystoblast - and might help explain this massive differential ...
In zebrafish embryos, factors involved in both axis induction and primordial germ cell (PGC) development are localized to the vegetal pole of the egg. However, upon egg activation axis induction factors experience an asymmetric off-center shift whereas PGC factors undergo symmetric animally-directed movement. We examined the spatial relationship between the proposed dorsal genes wnt8a and grip2a and the PGC factor dazl at the vegetal cortex. We find that RNAs for these genes localize to different cortical depths, with the RNA for the PGC factor dazl at a deeper cortical level than those for axis-inducing factors. In addition, and in contrast to the role of microtubules in the long-range transport of dorsal determinants, we find that germ line determinant transport depends on the actin cytoskeleton. Our results support a model in which vegetal cortex differential RNA transport behavior is facilitated by RNA localization along cortical depth and differential coupling to cortical transport ...
Background: Recent publications regarding the differentiation of stem cells to germ cells have motivated researchers to make new approaches in infertility. In vitro production of germ cells improves the understanding of differentiation process of male and female germ cells. Since using embryonic stem cells for this purpose has been associated ...
Biology Open provides rapid publication for scientifically sound observations and valid conclusions in developmental, cell, experimental and translational biology. Submit your paper for an easy and fast publication process. Recent developmental biology highlights in in BiO include work by Teramoto et al., which looks at the change in epithelial characteristics in the anterior foregut in the absence of SOX2.. ...
Hi everyone I posted a question on the histonet a week ago but I dont think I=20 explained my dilemma clearly enough. I am using alkaline phosphatase=20 histochemistry (not immunohistochemistry!) on PFA-fixed whole marsupial blastocysts and embryos to detect primordial germ cells=20 (PGCs). I use 1mg/ml Fast Blue salt and 1mg/ml Naphthol AS phosphate=20 sodium salt in 0.2M Tris buffer, pH 9.4 for the histochemistry, a=20 standard method for the detection of PGCs. The staining is good but I=20 have been told that it is not permanent. Ideally, after staining these embryos histochemically for PGCs, I would like to dehydrate,=20 paraffin- embed, section and then stain them immunohistochemically=20 (ie, with antibodies) for other germ cell markers and several growth=20 factors. Does anyone know of a histochemical method for the detection=20 of germ cells that would later permit me to do this? We have well-established methods for immunohistochemistry for several germ=20 cell markers in our lab. Thank ...
... Saga of Germ line Two step process; Primordial germ cells (PGCs) are determined in a specific location in the embryo PGCs migrate to the gonad and become
Germ cells (the cells that give rise to eggs and sperm) have special properties that enable them to serve their crucial role in development. The immortality and totipotency of the germ lineage allows germ cells to be passed from generation to generation and to produce all of the diverse cell types of the body in each generation. Our lab investigates the molecular mechanisms by which germ cells establish and maintain their identity, immortality, and totipotency, using the model organism C. elegans. We are currently focusing on the roles of chromatin regulators and how they transmit a memory of germline from parent germ cells to the germ cells in offspring ...
In previous studies, we have shown the exclusive expression of the Xtr gene in germ line cells of Xenopus and the occurrence of Xtr in germ line cells as well as early embryonic cells as a maternal factor (Ikema et al. 2002; Hiyoshi et al. 2005). Loss-of-function of Xtr in fertilized eggs using anti-Xtr antibody caused the lack of chromosome condensation and microtubule assembly, resulting in cleavage arrest (Hiyoshi et al. 2005). Since Xtr is a member of mRNP complex associated with mRNAs encoding the proteins such as XL-INCENP and RCC1 (Mostafa et al. 2009), which play an important role in karyokinesis (Ohtsubo et al. 1989; Mackay et al. 1998; Adams et al. 2001), the inhibition of karyokinesis progression induced by ablation of Xtr function was expected to be ascribable to translational suppression of these mRNAs. In Xenopus spermatogenesis, the amount of Xtr increases immediately after spermatogenic cells enter into meiotic phase (Hiyoshi et al. 2005). Therefore, Xtr was also thought to be ...
the end of the chlamydial developmental cycle. The longest incubation period in our setting was 46 hpi and as expected, we did not find an increased secretion
... The cells that give rise to the gametes are often set aside during cleavage. During development, these cells will differientate into
Embryonic germ cells are formed from embryonic progenitors through a highly complex differentiation process, recapitulation of which in vitro has proved challenging. Two new studies in The EMBO Journal report culture conditions for embryonic stem cell‐derived primordial germ cell‐like cells (PGCLCs) that enable global DNA demethylation (Ohta et al, 2017), and subsequent initiation of meiosis (Miyauchi et al, 2017), allowing future manipulations to elucidate mechanisms driving germ line differentiation.. See also: H Ohta et al (July 2017) and. H Miyauchi et al (November 2017) ...
Embryonic germ cells are formed from embryonic progenitors through a highly complex differentiation process, recapitulation of which in vitro has proved challenging. Two new studies in The EMBO Journal report culture conditions for embryonic stem cell‐derived primordial germ cell‐like cells (PGCLCs) that enable global DNA demethylation (Ohta et al, 2017), and subsequent initiation of meiosis (Miyauchi et al, 2017), allowing future manipulations to elucidate mechanisms driving germ line differentiation.. See also: H Ohta et al (July 2017) and. H Miyauchi et al (November 2017) ...