Primordial germ cells in the mouse embryo during gastrulation

Development ◽  
1990 ◽  
Vol 110 (2) ◽  
pp. 521-528 ◽  
Author(s):  
M. Ginsburg ◽  
M.H. Snow ◽  
A. McLaren
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells ◽  
Primitive Streak ◽  
Cell Types ◽  
Mesodermal Cell ◽  
Alp Activity ◽  
Cluster Area ◽  
Extraembryonic Mesoderm ◽  
Excised Tissue ◽  
Number Of Cells

With the aid of a whole-mount technique, we have detected a small cluster of alkaline phosphatase (ALP)-positive cells in whole mounts of mid-primitive-streak-stage embryos, 7–7 1/4 days post coitum (dpc). Within the cluster, about 8 cells contain a small cytoplasmic spot, intensely stained for ALP activity and possibly associated with an active Golgi complex. The cluster lies just posterior to the definitive primitive streak in the extraembryonic mesoderm, separated from the embryo by the amniotic fold. Towards the end of gastrulation, the number of cells containing the ALP-positive spot rises to between 50 and 80. Thereafter the number of cells in the extraembryonic cluster declines, and similar cells start to be seen in the mesoderm of the primitive streak and then in the endoderm. At 8 dpc, about 125 ALP-stained cells are found, mainly in the hindgut endoderm and also at the base of the allantois, their appearance and location at this stage agreeing closely with previous reports on primordial germ cells (PGCs). Embryos from which the cluster area has been removed at the 7-day stage are devoid of PGCs after culture for 48 h, whereas the excised tissue is rich in PGCs. We argue that the cells in the cluster are indeed primordial germ cells, at a stage significantly earlier than any reported previously. This would indicate that the PGC lineage in the mouse is set aside at least as early as 7 dpc, possibly as one of the first ‘mesodermal’ cell types to emerge, and that its differentiation, as expressed by ALP activity, is gradual.

MesP1: a novel basic helix-loop-helix protein expressed in the nascent mesodermal cells during mouse gastrulation

Development ◽  
1996 ◽  
Vol 122 (9) ◽  
pp. 2769-2778 ◽  
Author(s):  
Y. Saga ◽  
N. Hata ◽  
S. Kobayashi ◽  
T. Magnuson ◽  
M.F. Seldin ◽  
...  
Keyword(s):  
Germ Cells ◽  
Southern Hybridization ◽  
Primordial Germ Cells ◽  
Primitive Streak ◽  
Subtractive Hybridization ◽  
Hybridization Study ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Deficiency Gene ◽  
Extraembryonic Mesoderm

A subtractive hybridization strategy was used to isolate putative genes involved in the development of mouse primordial germ cells (PGC). Complimentary DNA was amplified on RNA isolated from the base of the allantois where PGC are located in the 7.5 days post coitum (dpc) mouse embryo. It was then subtracted by hybridization with cDNA amplified on RNA of the anterior region where PGC are absent. A novel gene thus isolated is designated as Mesp1 and encodes a possible transcription factor MesP1 containing a basic helix-loop-helix motif. Its earliest expression was observed at the onset of gastrulation, as early as 6.5 dpc, in the nascent mesodermal cells that first ingressed at the end of the primitive streak. These expressing cells in the lateral and extraembryonic mesoderm showed a wing-shaped distribution. Its initial expression was soon down-regulated at 7.5 dpc before the completion of gastrulation, except at the proximal end of the primitive streak which included the extraembryonic mesoderm and the base of allantois. At 8 dpc, the expression at the base of the allantois moved laterally. This distribution between 7.0 and 8.0 dpc was similar to that of PGC detected by the alkaline phosphatase activity. However, the expression of Mesp1 was down-regulated thereafter, when PGC entered in the migration stage. After birth, Mesp1 expression was detected only in mature testes, but in a different isoform from that expressed in the embryo. Mesp1 was mapped to the mid region of chromosome 7, near the mesodermal deficiency gene (mesd). However, a Southern hybridization study clearly showed that Mesp1 was distinctly different from mesd. The amino acid sequence and its expression pattern suggest that MesP1 plays an important role in the development of the nascent mesoderm including PGC.

Interactions between primordial germ cells play a role in their migration in mouse embryos

Development ◽  
1994 ◽  
Vol 120 (1) ◽  
pp. 135-141 ◽  
Author(s):  
M. Gomperts ◽  
M. Garcia-Castro ◽  
C. Wylie ◽  
J. Heasman
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells ◽  
Primitive Streak ◽  
Carbohydrate Antigen ◽  
Mature Stage ◽  
Conventional View ◽  
Embryonic Antigen ◽  
Hind Gut ◽  
Extraembryonic Mesoderm ◽  
Dorsal Mesentery

Primordial germ cells (PGCs) are the founder cell population of the gametes which form during the sexually mature stage of the life cycle. In the mouse, they arise early in embryogenesis, first becoming visible in the extraembryonic mesoderm, posterior to the primitive streak, at 7.5 days post coitum (d.p.c.). They subsequently become incorporated into the epithelium of the hind gut, from which they emigrate (9.5 d.p.c.) and move first into the dorsal mesentery (10.5 d.p.c.), and then into the genital ridges that lie on the dorsal body wall (11.5 d.p.c.). We have used confocal microscopy to study PGCs stained with an antibody that reacts with a carbohydrate antigen (Stage-Specific Embryonic Antigen-1, SSEA-1) carried on the PGC surface. This allows the study of the whole PGC surface, at different stages of their migration. The appearance of PGCs in tissue sections has given rise to the conventional view that they migrate as individuals, each arriving in turn at the genital ridge. In this paper, we show that PGCs leave the hind gut independently, but then extend long (up to 40 microns) processes, with which they link up to each other to form extensive networks. During the 10.5-11.5 d.p.c. period, these networks of PGCs aggregate into groups of tightly apposed cells in the genital ridges. As this occurs, their processes are lost, and their appearance suggests they are now non-motile. Furthermore, we find that PGCs taken from the dorsal mesentery at 10.5 d.p.c. perform the same sequence of movements in culture.(ABSTRACT TRUNCATED AT 250 WORDS)

Deletion of the selection cassette, but not cis-acting elements, in targeted Flk1-lacZ allele reveals Flk1 expression in multipotent mesodermal progenitors

Blood ◽  
2006 ◽  
Vol 107 (1) ◽  
pp. 111-117 ◽  
Author(s):  
Masatsugu Ema ◽  
Satoru Takahashi ◽  
Janet Rossant
Keyword(s):  
Growth Factor Receptor ◽  
Primitive Streak ◽  
Cell Types ◽  
Gene Encoding ◽  
Mesodermal Cell ◽  
Selection Cassette ◽  
Cis Acting ◽  
Endogenous Expression ◽  
Extraembryonic Mesoderm ◽  
Early Mouse

Abstract Flk1, the gene encoding the vascular endothelial growth factor receptor 2 (VEGFR-2), is a well-known marker for vascular and hematopoietic progenitors and is indispensable for normal hematopoiesis and vasculogenesis. Here we show that Flk1 expression in the early mouse embryo marks a broad spectrum of mesodermal progenitors exiting the primitive streak as well as later mesodermal cell types including some cardiomyocytes, portions of the somites, and all extraembryonic mesoderm cells. These findings made use of an Flk1-lacZ knock-in allele in which the neomycin selection cassette was removed, which resulted in full replication of the endogenous expression of Flk1. Targeted deletion of a region in intron 1 that has been proposed to direct endothelial expression produced no alteration in either endothelial or broader mesodermal expression of the Flk1-lacZ allele. Examination of lacZ expression in homozygotes for the Flk1lacZ neo-out allele revealed that lacZ-expressing mesodermal cells persisted in nonvascular regions. Thus, Flk1 expression marks progenitors with broad mesodermal potential but is not absolutely required for the development of all mesodermal lineages in which it is expressed.

Primordial germ cells in normal and transected duck blastoderms

Development ◽  
1968 ◽  
Vol 20 (3) ◽  
pp. 247-260
Author(s):  
Teresa Rogulska
Keyword(s):  
Chick Embryo ◽  
Blood Vessels ◽  
Germ Cells ◽  
Anterior Part ◽  
Primordial Germ Cells ◽  
Primitive Streak ◽  
Experimental Investigations ◽  
Suggestive Evidence ◽  
Area Pellucida

Suggestive evidence for the extragonadal origin of germ cells in birds was first presented by Swift (1914), who described primordial germ cells in the chick embryo at as early a stage as the primitive streak. According to Swift, primordial germ cells are originally located extra-embryonically in the anterior part of the blastoderm and occupy a crescent-shaped region (‘germinal crescent’) on the boundary between area opaca and area pellucida. Swift also found that primordial germ cells later enter into the blood vessels, circulate together with the blood throughout the whole blastoderm and finally penetrate into the genital ridges, where they become definitive germ cells. Swift's views have been confirmed in numerous descriptive and experimental investigations. Among the latter, the publications of Willier (1937), Simon (1960) and Dubois (1964a, b, 1965a, b, 1966) merit special attention. Dubois finally proved that the genital ridges exert a strong chemotactic influence on the primordial germ cells.

The effect of egg rotation on the differentiation of primordial germ cells in Xenopus laevis

Development ◽  
1985 ◽  
Vol 90 (1) ◽  
pp. 79-99
Author(s):  
J. H. Cleine ◽  
K. E. Dixon
Keyword(s):  
Xenopus Laevis ◽  
Germ Cells ◽  
Germ Plasm ◽  
Primordial Germ Cells ◽  
Intermediate Zone ◽  
Gastrula Stage ◽  
Tail Bud ◽  
Axis Orientation ◽  
Early Gastrula ◽  
Number Of Cells

Eggs of X. laevis were rotated (sperm entrance point downwards) either through 90° (1×90 embryos) or 180° in two 90° steps (2×90 embryos) at approximately 25–30 min postfertilization after cooling to 13°C. The embryos were kept in their off-axis orientation and cooled until the early gastrula stage. Rotation resulted in relocation of egg constituents with slight changes in the distribution of outer cortical and subcortical components and major changes in inner constituents where the heavy yolk and cytoplasm appeared to reorient as a single coherent unit to maintain their relative positions with respect to gravity. Development of rotated embryos was such that regions of the egg which normally give rise to posterior structures instead developed into anterior structures and vice versa. Germ plasm was displaced in the vegetal-dorsal-animal direction (the direction of rotation) and was segregated into dorsal micromeres and intermediate zone cells in 2×90 embryos and dorsal macromeres and intermediate zone cells in 1×90 embryos. In consequence, at the gastrula stage, cells containing germ plasm were situated closer to the dorsal lip of the blastopore after rotation — in 2×90 gastrulas around and generally above the dorsal lip. Hence, in rotated embryos, the cells containing germ plasm were invaginated earlier during gastrulation and therefore were carried further anteriorly in the endoderm to a mean position anterior to the midpoint of the endoderm. The number of cells containing germ plasm in rotated embryos was not significantly different from that in controls at all stages up to and including tail bud (stage 25). However at stages 46, 48 and 49 the number of primordial germ cells was reduced in 1×90 embryos in one experiment of three and in 2×90 embryos in all experiments. We tested the hypothesis that the decreased number of primordial germ cells in the genital ridges was due to the inability of cells to migrate to the genital ridges from their ectopic location in the endoderm. When anterior endoderm was grafted into posterior endodermal regions the number of primordial germ cells increased slightly or not at all suggesting that the anterior displacement of the cells containing germ plasm was not the only factor responsible for the decreased number of primordial germ cells in rotated embryos. Other possible explanations are discussed.

scholarly journals The spermatogenesis of acaris habena linton

1918 ◽  
Author(s):  
◽  
Hope Hibbard
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells ◽  
Growth Period ◽  
Number Of Cells

Text from pages 2-3: "In the development of spermatozoa, there are first differentiated in the embryo the primordial germ cells. These divide and subdivide until a large number of cells, known as spermatogonia, are formed. Then the cells begin to increase in size and following this growth period, there are two maturation divisions during which the chromatin content becomes reduced one half. The cells produced by these divisions become immediately the functional germ cells, or spermatozoa. It is the behavior of the chromosomes of Ascaris habena during the maturation divisions that is discussed in the following pages."

scholarly journals Chicken blastoderms and primordial germ cells possess a higher expression of DNA repair genes and lower expression of apoptosis genes to preserve their genome stability

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Deivendran Rengaraj ◽  
Sohyoung Won ◽  
Kyung Min Jung ◽  
Seung Je Woo ◽  
Haerang Lee ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Germ Cells ◽  
Genome Stability ◽  
Primordial Germ Cells ◽  
Cell Types ◽  
Repair Pathway ◽  
Apoptosis Pathway ◽  
Whole Transcriptome Sequencing ◽  
Apoptosis Pathways

AbstractDNA is susceptible to damage by various sources. When the DNA is damaged, the cell repairs the damage through an appropriate DNA repair pathway. When the cell fails to repair DNA damage, apoptosis is initiated. Although several genes are involved in five major DNA repair pathways and two major apoptosis pathways, a comprehensive understanding of those gene expression is not well-understood in chicken tissues. We performed whole-transcriptome sequencing (WTS) analysis in the chicken embryonic fibroblasts (CEFs), stage X blastoderms, and primordial germ cells (PGCs) to uncover this deficiency. Stage X blastoderms mostly consist of undifferentiated progenitor (pluripotent) cells that have the potency to differentiate into all cell types. PGCs are also undifferentiated progenitor cells that later differentiate into male and female germ cells. CEFs are differentiated and abundant somatic cells. Through WTS analysis, we identified that the DNA repair pathway genes were expressed more highly in blastoderms and high in PGCs than CEFs. Besides, the apoptosis pathway genes were expressed low in blastoderms and PGCs than CEFs. We have also examined the WTS-based expression profiling of candidate pluripotency regulating genes due to the conserved properties of blastoderms and PGCs. In the results, a limited number of pluripotency genes, especially the core transcriptional network, were detected higher in both blastoderms and PGCs than CEFs. Next, we treated the CEFs, blastoderm cells, and PGCs with hydrogen peroxide (H2O2) for 1 h to induce DNA damage. Then, the H2O2 treated cells were incubated in fresh media for 3–12 h to observe DNA repair. Subsequent analyses in treated cells found that blastoderm cells and PGCs were more likely to undergo apoptosis along with the loss of pluripotency and less likely to undergo DNA repair, contrasting with CEFs. These properties of blastoderms and PGCs should be necessary to preserve genome stability during the development of early embryos and germ cells, respectively.

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.

Germ cells and pluripotent stem cells in the mouse

2001 ◽  
Vol 13 (8) ◽  
pp. 661 ◽  
Author(s):  
Anne McLaren ◽  
Gabriela Durcova-Hills
Keyword(s):  
Growth Factors ◽  
Cell Lines ◽  
Germ Cells ◽  
Primordial Germ Cells ◽  
Embryonic Stem ◽  
Cell Types ◽  
Embryoid Bodies ◽  
Individual Growth ◽  
Developmental Potential

For many years, attempts to achieve long-term culture of mouse primordial germ cells (PGCs) proved unsuccessful, even when feeder layers were used and individual growth factors were added to the medium. However, when three growth factors were added simultaneously to the medium, some of the cells continued to proliferate indefinitely. Similar to embryonic stem cell lines, these embryonic germ (EG) cell lines were capable of giving rise to embryoid bodies in vitro, and colonizing all cell lineages in chimeras, including the germline. Initially, EG cells were made from PGCs before migration, 8.5 days post coitum (dpc), and after entry into the genital ridge, 11.5 and 12.5 dpc. New EG cell lines from 9.5 dpc (migrating) and 11.5 dpc PGCs, carrying either a LacZ or GFP transgene, are described here. The developmental potential of the new EG cell lines in vitro, in vivoin chimeras, and in tissue aggregates in organ culture was studied. The EG cells were compared with PGCs at the stage from which the EG cells were derived. The two cell types show several similarities, but also some differences in gene expression and cell behaviour, which require further exploration.

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