scholarly journals Induction of Primordial Germ Cells from Pluripotent Epiblast

2002 ◽  
Vol 2 ◽  
pp. 801-810 ◽  
Author(s):  
Ying Ying ◽  
Xiaoxia Qi ◽  
Guang-Quan Zhao
Keyword(s):  
Germ Cell ◽  
Cell Fate ◽  
Bone Morphogenetic Proteins ◽  
Germ Cells ◽  
Primordial Germ Cells ◽  
Cell Lineage ◽  
Close Relative ◽  
Cell Fate Specification ◽  
Visceral Endoderm ◽  
Receptor Complexes

The formation of germ cells during embryogenesis bears the ultimate importance for the continuation of every species. It becomes evident that mechanisms governing germ cell fate specification are not well conserved across the animal kingdom. In most of the invertebrate and nonmammalian vertebrate species, certain maternally derived factors are key to the establishment of germ cell lineage. In contrast, mouse primordial germ cells (PGCs) are induced from the pluripotent epiblast cells before and during gastrulation by the extraembryonic cell-derived signals. The molecular identity for some of these signals has recently been revealed by genetic and epiblast culture experiments. Both bone morphogenetic proteins 4 (Bmp4) and 8b (Bmp8b) are expressed in the extraembryonic ectoderm and are required for PGC formation. Furthermore, BMP4 or BMP8B alone are unable to induce PGCs from cultured epiblasts, while they can in combination, indicating they signal through separate receptor complexes. In addition, Bmp4 homozygous embryos cannot be induced to form PGCs by the synergistic action of BMP4 and BMP8B, suggesting that BMP4 proteins produced by pregastrula embryos are required for epiblast cells to maintain pluripotency. Moreover, Bmp2, a close relative of Bmp4, is expressed in visceral endoderm at the time of PGC specification, and inactivation of Bmp2 results in a reduction in PGC number, revealing a novel function of visceral endoderm in PGC generation in the mouse.

scholarly journals Ligand–Receptor Interactions Elucidate Sex-Specific Pathways in the Trajectory From Primordial Germ Cells to Gonia During Human Development

2021 ◽  
Vol 9 ◽  
Author(s):  
Arend W. Overeem ◽  
Yolanda W. Chang ◽  
Jeroen Spruit ◽  
Celine M. Roelse ◽  
Susana M. Chuva De Sousa Lopes
Keyword(s):  
Germ Cell ◽  
Signaling Pathways ◽  
Germ Cells ◽  
Tyrosine Kinases ◽  
Intracellular Localization ◽  
Primordial Germ Cells ◽  
Cell Lineage ◽  
Systematic Analysis ◽  
Receptor Interactions

The human germ cell lineage originates from primordial germ cells (PGCs), which are specified at approximately the third week of development. Our understanding of the signaling pathways that control this event has significantly increased in recent years and that has enabled the generation of PGC-like cells (PGCLCs) from pluripotent stem cells in vitro. However, the signaling pathways that drive the transition of PGCs into gonia (prospermatogonia in males or premeiotic oogonia in females) remain unclear, and we are presently unable to mimic this step in vitro in the absence of gonadal tissue. Therefore, we have analyzed single-cell transcriptomics data of human fetal gonads to map the molecular interactions during the sex-specific transition from PGCs to gonia. The CellPhoneDB algorithm was used to identify significant ligand–receptor interactions between germ cells and their sex-specific neighboring gonadal somatic cells, focusing on four major signaling pathways WNT, NOTCH, TGFβ/BMP, and receptor tyrosine kinases (RTK). Subsequently, the expression and intracellular localization of key effectors for these pathways were validated in human fetal gonads by immunostaining. This approach provided a systematic analysis of the signaling environment in developing human gonads and revealed sex-specific signaling pathways during human premeiotic germ cell development. This work serves as a foundation to understand the transition from PGCs to premeiotic oogonia or prospermatogonia and identifies sex-specific signaling pathways that are of interest in the step-by-step reconstitution of human gametogenesis in vitro.

scholarly journals Phase Transitioned Nuclear Oskar Promotes Cell Division of Drosophila Primordial Germ Cells

2018 ◽  
Author(s):  
Kathryn E. Kistler ◽  
Tatjana Trcek ◽  
Thomas R. Hurd ◽  
Ruoyu Chen ◽  
Feng-Xia Liang ◽  
...  
Keyword(s):  
Germ Cell ◽  
Cell Fate ◽  
Germ Cells ◽  
Cell Function ◽  
Primordial Germ Cells ◽  
Nuclear Localization Sequence ◽  
Cell Systems ◽  
Germ Granules ◽  
Localization Sequence ◽  
Transcriptional Gene Regulation

ABSTRACTGerm granules are non-membranous ribonucleoprotein granules deemed the hubs for post-transcriptional gene regulation and functionally linked to germ cell fate across species. Little is known about the physical properties of germ granules and how these relate to germ cell function. Here we study two types of germ granules in the Drosophila embryo: cytoplasmic germ granules that instruct primordial germ cells (PGCs) formation and nuclear germ granules within early PGCs with unknown function. We show that cytoplasmic and nuclear germ granules are phase transitioned condensates nucleated by Oskar protein that display liquid as well as hydrogel-like properties. Focusing on nuclear granules, we find that Oskar drives their formation in heterologous cell systems. Multiple, independent Oskar protein domains synergize to promote granule phase separation. Deletion of Oskar’s nuclear localization sequence specifically ablates nuclear granules in cell systems. In the embryo, nuclear germ granules promote germ cell divisions thereby increasing PGC number for the next generation.

scholarly journals Purification of mouse primordial germ cells by Nycodenz

Reproduction ◽  
2003 ◽  
pp. 667-675 ◽  
Author(s):  
T Mayanagi ◽  
R Kurosawa ◽  
K Ohnuma ◽  
A Ueyama ◽  
K Ito ◽  
...  
Keyword(s):  
Germ Cell ◽  
Germ Cells ◽  
Specific Antibody ◽  
Membrane Surface ◽  
Primordial Germ Cells ◽  
Primordial Germ Cell ◽  
Specific Antigen ◽  
Cell Lineage ◽  
New Method ◽  
Purification Method

Primordial germ cells are important cells for the study of germ cell lineage. It has proved difficult to obtain highly purified primordial germ cells for preparation of a specific antibody. In the present study, a new method for purifying mouse primordial germ cells was developed using a Nycodenz gradient. Furthermore, the polyclonal anti-mouse primordial germ cells IgG derived from mouse primordial germ cells was prepared. As this IgG reacted only with primordial germ cells obtained at day 12.5 after mating, this antibody appeared to recognize the stage-specific antigen of primordial germ cells. One reason that a continuous primordial germ cell marker has not been obtained is because the purity of the primordial germ cells used has been too low to prepare the antibody. This new method represents a significant improvement in the purification of primordial germ cells; it is simpler than previous methods, and produced mouse primordial germ cells with a purity of more than 95%. In addition, the separation reagent Nycodenz is non-toxic and achieved separation of primordial germ cells without attachment of antibodies against the primordial germ cell membrane surface. This new purification method and stage-specific antibody will be useful for the analysis of the mechanisms of primordial germ cell migration.

scholarly journals Functional reconstruction of NANOS3 expression in the germ cell lineage by a novel transgenic reporter reveals distinct subcellular localizations of NANOS3

Reproduction ◽  
2010 ◽  
Vol 139 (2) ◽  
pp. 381-393 ◽  
Author(s):  
Masashi Yamaji ◽  
Takashi Tanaka ◽  
Mayo Shigeta ◽  
Shinichiro Chuma ◽  
Yumiko Saga ◽  
...  
Keyword(s):  
Germ Cell ◽  
Germ Cells ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Primordial Germ Cells ◽  
Cell Lineage ◽  
Regulatory Elements ◽  
Initiation Factor ◽  
Processing Bodies

Mutations of RNA-binding proteins such as NANOS3, TIAL1, and DND1 in mice have been known to result in the failure of survival and/or proliferation of primordial germ cells (PGCs) soon after their fate is specified (around embryonic day (E) 8.0), leading to the infertility of these animals. However, the mechanisms of actions of these RNA-binding proteins remain largely unresolved. As a foundation to explore the role of these RNA-binding proteins in germ cells, we established a novel transgenic reporter strain that expresses NANOS3 fused with EGFP under the control of Nanos3 regulatory elements. NANOS3–EGFP exhibited exclusive expression in PGCs as early as E7.25, and continued to be expressed in female germ cells until around E14.5 and in male germ cells throughout the fetal period with declining expression levels after E16.5. NANOS3–EGFP resumed strong expression in postnatal spermatogonia and continued to be expressed in undifferentiated spermatogonial cells in adults. Importantly, the Nanos3–EGFP transgene rescued the sterile phenotype of Nanos3 homozygous mutants, demonstrating the functional equivalency of NANOS3–EGFP with endogenous NANOS3. We found that throughout germ cell development, a predominant amount of  NANOS3–EGFP co-localized with TIAL1 (also known as TIAR) and phosphorylated eukaryotic initiation factor 2α, markers for the stress granules, whereas a fraction of it showed co-localization with DCP1A, a marker for the processing bodies. On the other hand, NANOS3–EGFP did not co-localize with Tudor domain-containing protein 1, a marker for the intermitochondrial cements, in spermatogenic cells. These findings unveil the presence of distinct posttranscriptional regulations in PGCs soon after their specification, for which RNA-binding proteins such as NANOS3 and TIAL1 would play critical functions.

Events in the germ cell lineage after entry of the primordial germ cells into the genital ridges in normal and u.v.-irradiated Xenopus laevis

Development ◽  
1977 ◽  
Vol 41 (1) ◽  
pp. 33-46
Author(s):  
Brigitta Züst ◽  
K. E. Dixon
Keyword(s):  
Xenopus Laevis ◽  
Germ Cell ◽  
Germ Cells ◽  
Dorsal Root ◽  
Primordial Germ Cells ◽  
Cell Lineage ◽  
Cell Stage ◽  
Comparison Of The Results ◽  
New Generation

Approximately 20–25 primordial germ cells leave the endoderm between stages 38–41 and localize in the dorsal root of the mesentery by stage 43/44. At this time all the cells contain large quantities of yolk which is gradually resorbed. The cells begin dividing between stages 48–52. The number and size of the germ cells were measured in tadpoles between stages 48–54 of development. The results indicate that in females the germ cells divide more often than in males. In both sexes the mitoses are grossly unequal, leading to the formation of a new generation of germ cells which are considerably smaller (one-tenth to one-fifth) than the size of the primordial germ cells at stage 48. The germ cells in male tadpoles at stage 54 are larger than in female tadpoles at the same stage. In tadpoles which developed from eggs irradiated in the vegetal hemisphere with u.v. light at the 2- to 4-cell-stage, primordial germ cells migrate into the genital ridges much later (stage 46–48) than in unirradiated embryos. They also differ morphologically from germ cells in control animals at this stage in that they are approximately one-tenth the size, lacking yolk in the cytoplasm and have a more highly lobed nucleus. Comparison of the results in unirradiated and irradiated animals suggests that the germ cell lineage is composed of a series of ordered, predictable events, and serious disruption of one of the events deranges later events.

scholarly journals Extensive nuclear gyration and pervasive non-genic transcription during primordial germ cell development in zebrafish

Development ◽  
2020 ◽  
pp. dev.193060
Author(s):  
Stefan Redl ◽  
Antonio M. de Jesus Domingues ◽  
Edoardo Caspani ◽  
Stefanie Möckel ◽  
Willi Salvenmoser ◽  
...  
Keyword(s):  
Germ Cell ◽  
Cell Fate ◽  
Germ Cells ◽  
Primordial Germ Cells ◽  
Primordial Germ Cell ◽  
Genital Ridge ◽  
Non Coding Rna ◽  
Pathway Activation ◽  
Pirna Pathway ◽  
Time Point

Primordial germ cells (PGCs) are the precursors of germ cells, which migrate to the genital ridge during early development. Relatively little is known about PGCs after their migration. We studied this post-migratory stage using microscopy and sequencing techniques, and found that many PGC-specific genes, including genes known to induce PGC fate in the mouse, are only activated several days after migration. At this same time point, PGC nuclei become extremely gyrated, displaying general broad opening of chromatin and high levels of intergenic transcription. This is accompanied by changes in nuage morphology, expression of large loci (PGC-Expressed non-coding RNA Loci, PERLs) that are enriched for retro-transposons and piRNAs, and a rise in piRNA biogenesis signatures. Interestingly, no nuclear Piwi protein could be detected at any time point, indicating that the zebrafish piRNA pathway is fully cytoplasmic. Our data show that the post-migratory stage of zebrafish PGCs holds many cues to both germ cell fate establishment and piRNA pathway activation.

scholarly journals Extensive nuclear gyration and pervasive non-genic transcription during primordial germ cell development in zebrafish

2020 ◽  
Author(s):  
Stefan Redl ◽  
Antonio M. de Jesus Domingues ◽  
Stefanie Möckel ◽  
Willi Salvenmoser ◽  
Maria Mendez-Lago ◽  
...  
Keyword(s):  
Germ Cell ◽  
Cell Fate ◽  
Early Development ◽  
Germ Cells ◽  
Primordial Germ Cells ◽  
Primordial Germ Cell ◽  
Piwi Protein ◽  
Genital Ridge ◽  
Pathway Activation ◽  
Pirna Pathway

SUMMARYPrimordial germ cells (PGCs) are the precursors of germ cells, which migrate to the genital ridge during early development. Relatively little is known about PGCs after their migration. We studied this post-migratory stage using microscopy and sequencing techniques, and found that many PGC-specific genes, including genes known to induce PGC fate in the mouse, are only activated several days after migration. At this same timepoint, PGC nuclei become extremely gyrated, displaying general opening of chromatin and high levels of transcription. This is accompanied by changes in nuage morphology, expression of large loci, named PERLs, enriched for retro-transposons and piRNAs, and a rise in piRNA biogenesis signatures. Interestingly, no nuclear Piwi protein could be detected at any timepoint, indicating that the zebrafish piRNA pathway is fully cytoplasmic. Our data show that the post-migratory stage of zebrafish PGCs holds many cues to both germ cell fate establishment and piRNA pathway activation.

Mouse embryos lacking Smad1 signals display defects in extra-embryonic tissues and germ cell formation

Development ◽  
2001 ◽  
Vol 128 (18) ◽  
pp. 3609-3621 ◽  
Author(s):  
Kimberly D. Tremblay ◽  
N. Ray Dunn ◽  
Elizabeth J. Robertson
Keyword(s):  
Germ Cell ◽  
Germ Cells ◽  
Es Cells ◽  
Primordial Germ Cells ◽  
Primordial Germ Cell ◽  
Mouse Embryos ◽  
Visceral Endoderm ◽  
Mouse Development ◽  
Embryonic Tissues ◽  
Germ Cell Specification

The Smad proteins are important intracellular mediators of the transforming growth factor β (TGFβ) family of secreted growth factors. Smad1 is an effector of signals provided by the bone morphogenetic protein (BMP) sub-group of TGFβ molecules. To understand the role of Smad1 in mouse development, we have generated a Smad1 loss-of-function allele using homologous recombination in ES cells. Smad1−/− embryos die by 10.5 dpc because they fail to connect to the placenta. Mutant embryos are first recognizable by 7.0 dpc, owing to a characteristic localized outpocketing of the visceral endoderm at the posterior embryonic/extra-embryonic junction, accompanied by a dramatic twisting of the epiblast and nascent mesoderm. Chimera analysis reveals that these two defects are attributable to a requirement for Smad1 in the extra-embryonic tissues. By 7.5 dpc, Smad1-deficient embryos show a marked impairment in allantois formation. By contrast, the chorion overproliferates, is erratically folded within the extra-embryonic space and is impeded in proximal migration. BMP signals are known to be essential for the specification and proliferation of primordial germ cells. We find a drastic reduction of primordial germ cells in Smad1-deficient embryos, suggesting an essential role for Smad1-dependent signals in primordial germ cell specification. Surprisingly, despite the key involvement of BMP signaling in tissues of the embryo proper, Smad1-deficient embryos develop remarkably normally. An examination of the expression domains of Smad1, Smad5 and Smad8 in early mouse embryos show that, while Smad1 is uniquely expressed in the visceral endoderm at 6.5 dpc, in other tissues Smad1 is co-expressed with Smad5 and/or Smad8. Collectively, these data have uncovered a unique function for Smad1 signaling in coordinating the growth of extra-embryonic structures necessary to support development within the uterine environment.

scholarly journals Phase transitioned nuclear Oskar promotes cell division of Drosophila primordial germ cells

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Kathryn E Kistler ◽  
Tatjana Trcek ◽  
Thomas R Hurd ◽  
Ruoyu Chen ◽  
Feng-Xia Liang ◽  
...  
Keyword(s):  
Germ Cell ◽  
Cell Fate ◽  
Germ Cells ◽  
Cell Function ◽  
Primordial Germ Cells ◽  
Drosophila Embryo ◽  
Nuclear Localization Sequence ◽  
Cell Systems ◽  
Germ Granules ◽  
Localization Sequence

Germ granules are non-membranous ribonucleoprotein granules deemed the hubs for post-transcriptional gene regulation and functionally linked to germ cell fate across species. Little is known about the physical properties of germ granules and how these relate to germ cell function. Here we study two types of germ granules in the Drosophila embryo: cytoplasmic germ granules that instruct primordial germ cells (PGCs) formation and nuclear germ granules within early PGCs with unknown function. We show that cytoplasmic and nuclear germ granules are phase transitioned condensates nucleated by Oskar protein that display liquid as well as hydrogel-like properties. Focusing on nuclear granules, we find that Oskar drives their formation in heterologous cell systems. Multiple, independent Oskar protein domains synergize to promote granule phase separation. Deletion of Oskar’s nuclear localization sequence specifically ablates nuclear granules in cell systems. In the embryo, nuclear germ granules promote germ cell divisions thereby increasing PGC number for the next generation.

scholarly journals Specification of germ cell fate in mice

2003 ◽  
Vol 358 (1436) ◽  
pp. 1363-1370 ◽  
Author(s):  
Mitinori Saitou ◽  
Bernhard Payer ◽  
Ulrike C. Lange ◽  
Sylvia Erhardt ◽  
Sheila C. Barton ◽  
...  
Keyword(s):  
Germ Cell ◽  
Cell Fate ◽  
Germ Cells ◽  
Transcriptional Repression ◽  
Single Cell Analysis ◽  
Primordial Germ Cells ◽  
Cell Specification ◽  
Signalling Molecules ◽  
Germ Cell Specification

An early fundamental event during development is the segregation of germ cells from somatic cells. In many organisms, this is accomplished by the inheritance of preformed germ plasm, which apparently imposes transcriptional repression to prevent somatic cell fate. However, in mammals, pluripotent epiblast cells acquire germ cell fate in response to signalling molecules. We have used single cell analysis to study how epiblast cells acquire germ cell competence and undergo specification. Germ cell competent cells express Fragilis and initially progress towards a somatic mesodermal fate. However, a subset of these cells, the future primordial germ cells (PGCs), then shows rapid upregulation of Fragilis with concomitant transcriptional repression of a number of genes, including Hox and Smad genes. This repression may be a key event associated with germ cell specification. Furthermore, PGCs express Stella and other genes, such as Oct – 4 that are associated with pluripotency. While these molecules are also detected in mature oocytes as maternally inherited factors, their early role is to regulate development and maintain pluripotency, and they do not serve the role of classical germline determinants.

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