Memoirs: The Origin and Migration of the Primordial Germ-cells of Sphenodon punctatus

1932 ◽  
Vol s2-75 (298) ◽  
pp. 251-282
Author(s):  
MARGARET TRIBE ◽  
F.W. ROGERS BRAMBELL
Keyword(s):  
Germ Cells ◽  
Early Stage ◽  
Venous Blood ◽  
Primordial Germ Cells ◽  
Blood Stream ◽  
Yolk Sac ◽  
Amoeboid Movement ◽  
Stage Of Development ◽  
Sphenodon Punctatus ◽  
And Migration

1. The primordial germ-cells of Sphenodon originate in the yolk-sac endoderm of the area opaca all round the embiyo, but chiefly in a crescentic area in front of it. 2. They differentiate first at a very early stage of development before the differentiation of the medullary plate. 3. The primordial germ-cells are characterized by their very large size, in comparison with all the other embryonal cells, and by their content of small yolk-spherules which are sub-equal in size. 4. The primordial germ-cells migrate through the yolk-sac endoderm and mesoderm, apparently by their own power of amoeboid movement. Many of them enter the blood-islands and the sinus terminalis. 5. The primordial germ-cells enter the embryo either (1) passively in the venous blood-stream, or (2) actively by migration through the extra-embryonal endoderm and splanchnic mesoderm into the lateral walls and the mesentery of the midgut groove. 6. The primordial germ-cells in the circulation reach the neighbourhood of the germinal ridges in the dorsal aorta or its branches. They then penetrate the walls of the vessels and migrate through the intervening tissues, together with those that have reached the base of the mid-gut mesentery by way of the splanchnic mesoderm and the mid-gut wall, to the germinal ridges. 7. Many primordial germ-cells get lost during their migration. This is especially true of those travelling in the blood-stream. Such aberrant primordial germ-cells are found occasionally in almost any part of the embryo,, but occur most often in the head, especially in the region of the fore-brain. They ultimately disappear. 8. The primordial germ-cells enter the forming germinal ridges before the coelomic epithelium covering them has begun to proliferate. 9. The primordial germ-cells, having reached the germinal ridges, lose their characteristic yolk-content and enter on the prophase of the heterotypic division.

140 LOCALIZATION OF PRIMORDIAL GERM CELLS IN DAY 21 BOVINE EMBRYOS

2007 ◽  
Vol 19 (1) ◽  
pp. 188
Author(s):  
N. I. Alexopoulos ◽  
N. T. D'Cruz ◽  
P. Maddox-Hyttel
Keyword(s):  
Neural Tube ◽  
Germ Cells ◽  
Primordial Germ Cells ◽  
Yolk Sac ◽  
Bovine Embryos ◽  
Surface Ectoderm ◽  
Oct4 Expression ◽  
Visceral Mesoderm ◽  
Stage Of Development

In most animal species, germ cell precursors, i.e., primordial germ cells (PGCs), arise from the epiblast and then migrate to the future gonadal ridge during development. At least in the mouse, PGCs may be cultured as embryonic germ cells that remain pluripotent. PGCs are the only cells in which OCT4 expression is maintained after gastrulation. The present study aimed at identifying the localization of PGCs in Day 21 in vivo-derived bovine embryos by immunohistochemical staining against OCT4. Six embryos were obtained after slaughter of superovulated heifers 21 days after insemination. The uterine tracts were flushed and embryos fixed, paraffin-embedded, and processed for immunohistochemistry. Embryos were sagitally sectioned, and selected serial sections were immunohistochemically stained for OCT4 to identify potential PGCs. Two embryos were at the neural groove stage. At this stage of development, the primitive gut had not yet been abstricted from the yolk sac and the allantois was not visible. A weak homogeneous OCT4 staining was localized to nuclei in a well-defined region of the epiblast, which was in the process of a gradual anterior to posterior differentiation into neural and surface ectoderm. Moreover, a strong OCT4 staining was localized to a few scattered cells found in the visceral mesoderm associated with the yolk sac in the region of the endoderm-hypoblast transition at some distance from the embryo proper. Four embryos were at the neural tube/somite stage. At this stage of development, the primitive gut had been defined and only the midgut was connected to the yolk sac. Furthermore, the allantois was visible as an anchor-shaped structure at the posterior end of the embryo. A strong OCT4 staining was found in nuclei of solitary cells in the endoderm and its associated visceral mesoderm of the ventral aspect of the mid and hindgut. The described OCT4 staining corresponds well with previous findings in the pig, in which presumptive PGCs are found in the endoderm epithelium during the neural groove stage. Later, during the early somite stages, they are localized in the endoderm and visceral mesoderm of the yolk sac and allantois, and in later somite stages, they are found in the developing genital ridge. This is, however, the first study to demonstrate the localization of these cells, at least by OCT4 staining, in bovine embryos at the neural groove and neural tube/somite stages.

Random X-chromosome inactivation in female primordial germ cells in the mouse

Development ◽  
1981 ◽  
Vol 64 (1) ◽  
pp. 251-258
Author(s):  
Andy McMahon ◽  
Mandy Fosten ◽  
Marilyn Monk
Keyword(s):  
X Chromosome ◽  
Germ Cells ◽  
Germ Line ◽  
Primordial Germ Cells ◽  
Phosphoglycerate Kinase ◽  
X Chromosome Inactivation ◽  
Yolk Sac ◽  
Chromosome Inactivation ◽  
X Chromosomes

The pattern of expression of the two X chromosomes was investigated in pre-meiotic germ cells from 12½-day-old female embryos heterozygous for the variant electrophoretic forms of the X-linked enzyme phosphoglycerate kinase (PGK-1). If such germ cells carry the preferentially active Searle's translocated X chromosome (Lyon, Searle, Ford & Ohno, 1964), then only the Pgk-1 allele on this chromosome is expressed. This confirms Johnston's evidence (1979,1981) that Pgk-1 expression reflects a single active X chromosome at this time. Extracts of 12½-day germ cells from heterozygous females carrying two normal X chromosomes show both the A and the B forms of PGK; since only one X chromosome in each cell is active, different alleles must be expressed in different cells, suggesting that X-chromosome inactivation is normally random in the germ line. This result makes it unlikely that germ cells are derived from the yolk-sac endoderm where the paternally derived X chromosome is preferentially inactivated. In their pattern of X-chromosome inactivation, germ cells evidently resemble other tissues derived from the epiblast.

The use of ‘normal’ and ‘transformed’ gynandromorphs in mapping the primordial germ cells and the gonadal mesoderm in Drosophila

Development ◽  
1976 ◽  
Vol 35 (3) ◽  
pp. 607-616
Author(s):  
W. J. Gehring ◽  
E. Wieschaus ◽  
M. Holliger
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells ◽  
Cell Lineage ◽  
Ventral Side ◽  
Drosophila Embryo ◽  
The Real ◽  
Genital Disc ◽  
Stage Of Development ◽  
Data Support ◽  
Blastoderm Stage

The primordial germ cells and the gonadal mesoderm were mapped in the Drosophila embryo by analyzing the patterns of mosaicism in ‘normal’ and ‘transformed’ gynandromorphs. Relative to the adult cuticular markers the germ cells map as the posterior moststructure, which coincides with their known location in the blastoderm embryo. These data support the hypothesis that the gynandromorph map reflects the real position of the pri-mordia in the embryo. Since after the blastoderm stage the primordial germ cells migrateanteriorly these data also indicate that the map in fact corresponds to the blastoderm stageand not to a later stage of development. The genital disc maps as a single median primordium anterior and ventral to the germ cells, the gonadal mesoderm is located anterior to the genital disc and also forms a single median primordium on the ventral side of the embryo. The primordia for the genital disc and the gonadal mesoderm are unusually large in size, which presumably reflects some indeterminacy of the cell lineage leading to an ‘expansion’ of the map.

scholarly journals Bayesian inference of transcriptional branching identifies regulators of early germ cell development in humans

2017 ◽  
Author(s):  
Christopher A. Penfold ◽  
Anastasiya Sybirna ◽  
John Reid ◽  
Aracely Castillo Venzor ◽  
Elena Drousioti ◽  
...  
Keyword(s):  
Cell Fate ◽  
Germ Cells ◽  
Temporal Dynamics ◽  
Primordial Germ Cells ◽  
Series Data ◽  
Human Embryos ◽  
Marker Genes ◽  
Cell Fate Decisions ◽  
Stage Of Development

AbstractDuring embryonic development, cells undertake a series of fate decisions to form a complete organism comprised of various cell types, epitomising a branching process. A striking example of branching occurs in humans around the time of implantation, when primordial germ cells (PGCs), precursors of sperm and eggs, and somatic lineages are specified. Due to inaccessibility of human embryos at this stage of development, understanding the mechanisms of PGC specification remains difficult. The integrative modelling of single cell transcriptomics data from embryos and appropriate in vitro models should prove to be a useful resource for investigating this system, provided that the cells can be suitably ordered over a developmental axis. Unfortunately, most methods for inferring cell ordering were not designed with structured (time series) data in mind. Although some probabilistic approaches address these limitations by incorporating prior information about the developmental stage (capture time) of the cell, they do not allow the ordering of cells over processes with more than one terminal cell fate. To investigate the mechanisms of PGC specification, we develop a probabilistic pseudotime approach, branch-recombinant Gaussian process latent variable models (B-RGPLVMs), that use an explicit model of transcriptional branching in individual marker genes, allowing the ordering of cells over developmental trajectories with arbitrary numbers of branches. We use first demonstrate the advantage of our approach over existing pseudotime algorithms and subsequently use it to investigate early human development, as primordial germ cells (PGCs) and somatic cells diverge. We identify known master regulators of human PGCs, and predict roles for a variety of signalling pathways, transcription factors, and epigenetic modifiers. By concentrating on the earliest branched signalling events, we identified an antagonistic role for FGF receptor (FGFR) signalling pathway in the acquisition of competence for human PGC fate, and identify putative roles for PRC1 and PRC2 in PGC specification. We experimentally validate our predictions using pharmacological blocking of FGFR or its downstream effectors (MEK, PI3K and JAK), and demonstrate enhanced competency for PGC fate in vitro, whilst small molecule inhibition of the enzymatic component of PRC1/PRC2 reveals reduced capacity of cells to form PGCs in vitro. Thus, B-RGPLVMs represent a powerful and flexible data-driven approach for dissecting the temporal dynamics of cell fate decisions, providing unique insights into the mechanisms of early embryogenesis. Scripts relating to this analysis are available from: https://github.com/cap76/PGCPseudotime

scholarly journals Embryonic Annexes

2018 ◽  
Vol 1 (4) ◽  
pp. 301-309
Author(s):  
Mariana Rojas ◽  
Ángel Rodríguez
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells ◽  
Chorionic Villus ◽  
Yolk Sac ◽  
Placental Lactogen ◽  
Mechanical Trauma ◽  
Temperature Changes ◽  
Suspensory Ligament ◽  
Different Types ◽  
Extraembryonic Membranes

In vertebrates, depending on the environment in which an embryo develops, different types of extraembryonic membranes are formed. In placental mammals the following extraembryonic membranes are formed: amnion, yolk sac, allantois, chorion and placenta. Extraembryonic membranes perform functions vital to the embryo. The amnion protects the embryo from drying, the mechanical trauma, temperature changes and adhesions which can distort it. The yolk sac is present in all vertebrates. In mammals allows the formation of the first blood vessels and the first blood, home to the primordial germ cells for some time; however, in fish and birds these have nutritional importance. In birds and mammals such as cattle, sheep and pig the allantois receives urinary wastes; this structure also contributes part of the bladder and at the time of birth becomes the suspensory ligament, urachus. The chorion form chorionic villus, which can produce hormones such as chorionic gonadotropin and human placental lactogen. A portion of the chorionic sac helps form the placenta.

Proliferation and migration of primordial germ cells during compensatory growth in mouse embryos

Development ◽  
1981 ◽  
Vol 64 (1) ◽  
pp. 133-147
Author(s):  
P. P. L. Tam ◽  
M. H. L. Snow
Keyword(s):  
Mitomycin C ◽  
Germ Cells ◽  
Compensatory Growth ◽  
Primordial Germ Cells ◽  
Primordial Germ Cell ◽  
Primitive Streak ◽  
Mouse Embryos ◽  
Newborn Mice ◽  
Embryonic Life ◽  
And Migration

Primitive-streak-stage mouse embryos were treated with Mitomycin C injected intraperitoneally into pregnant females at 6·75–7·0 days post coitum. The newborn mice developed poorly and mortality was high during the suckling period. Many weaned survivors showed impaired fertility and poor breeding performance. Histological examination revealed a paucity of germ cells in the adult gonads. The deficiency was mainly caused by a severe reduction of the primordial germ cell population in early embryonic life, which was not fully compensated for during the compensatory growth phase of the Mitomycin C-treated embryo. Also contributing to such impaired fertility were retarded migration of the primordial germ cells into the genital ridges, poor development of the foetal gonad and secondary loss of the germ cells during gametogenesis in males.

scholarly journals Inter-species transplantation and migration of primordial germ cells in cyprinid fish

2010 ◽  
Vol 54 (10) ◽  
pp. 1479-1484 ◽  
Author(s):  
Taiju Saito ◽  
Rie Goto-Kazeto ◽  
Takafumi Fujimoto ◽  
Yutaka Kawakami ◽  
Katsutoshi Arai ◽  
...  
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells ◽  
Cyprinid Fish ◽  
And Migration

scholarly journals PSVII-19 Characterization and Migration of Cultured Quail Primordial Germ Cells from Embryonic Blood and Gonad.

2018 ◽  
Vol 96 (suppl_3) ◽  
pp. 354-354
Author(s):  
S Yakhkeshi ◽  
S Rahimi ◽  
M Sharafi ◽  
S Hassani ◽  
G Shahverdi ◽  
...  
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells ◽  
And Migration

scholarly journals Highly efficient genome modification of cultured primordial germ cells with lentiviral vectors to generate transgenic songbirds

2020 ◽  
Author(s):  
Ivana Gessara ◽  
Falk Dittrich ◽  
Moritz Hertel ◽  
Staffan Hildebrand ◽  
Alexander Pfeifer ◽  
...  
Keyword(s):  
Zebra Finch ◽  
Germ Cells ◽  
Fluorescent Protein ◽  
Vocal Communication ◽  
Primordial Germ Cells ◽  
Vocal Learning ◽  
Lentiviral Vectors ◽  
Blood Stream ◽  
Stem Cell Markers ◽  
Highly Efficient

SUMARYThe ability to genetically manipulate organisms has led to significant insights in functional genomics in many species. In birds, manipulation of the genome is hindered by the inaccessibility of the one-cell embryo. During embryonic development, avian primordial germ cells (PGCs) migrate through the blood stream and reach the gonadal anlage; where they develop into mature germ cells. Here, we explored the use of PGCs to produce transgenic offspring in the zebra finch, which is a major animal model for sexual brain differentiation, vocal learning and vocal communication. Zebra finch PGCs (zfPGCs) obtained from embryonic blood significantly proliferated when cultured in an optimized culture medium and conserved the expression of germ and stem cell markers. Transduction of cultured zfPGCs with lentiviral vectors was highly efficient leading to strong expression of the enhanced green fluorescent protein (eGFP). Transduced zfPGCs were injected into the host embryo and transgenic songbirds were successfully generated.

The role of the cell surface in the migration of primordial germ cells in early chick embryos: effects of concanavalin A

Development ◽  
1978 ◽  
Vol 46 (1) ◽  
pp. 5-20
Author(s):  
H. Lee ◽  
N. Karasanyi ◽  
R. G. Nagele
Keyword(s):  
Cell Surface ◽  
Germ Cells ◽  
Concanavalin A ◽  
Primordial Germ Cells ◽  
Sublethal Dose ◽  
Chick Embryos ◽  
Con A ◽  
And Migration ◽  
Coat Material

Effects of concanavalin A (Con A) on the morphology and migration of primordial germ cells (PGCs) in stage-6 to -12 chick embryos were investigated. Con A, at a sublethal dose (10µg/ml), inhibited migration of PGCs from the germinal crescent area to other parts of the embryo. Affected PGCs were more rounded without the usual cytoplasmic extensions, but the integrity of other structures was unaffected. Nearly identical results were obtained with another lectin, wheat germ agglutinin (10µg/ml). Histochemistry using Con A-horseradish peroxidase revealed that PGCs in control embryos had a thin, rather uniform layer of extracellular coat material (ECM). Con A appeared to alter the distribution of ECM on PGCs, i.e. some parts of the cell surface were devoid of any detectable ECM, while others had small, scattered patches of ECM. Con A effects were alleviated by α-methyl-d-mannoside. Overall results of the present study indicated that the observed inhibition of PGC migration in early chick embryos is a consequence of Con A-induced alterations of cell surface properties.

Sign in / Sign up

Export Citation Format

Share Document