scholarly journals A zebrafish nanos-related gene is essential for the development of primordial germ cells

2001 ◽  
Vol 15 (21) ◽  
pp. 2877-2885
Author(s):  
Marion Köprunner ◽  
Christine Thisse ◽  
Bernard Thisse ◽  
Erez Raz
Keyword(s):  
Germ Cells ◽  
Essential Role ◽  
Germ Plasm ◽  
Primordial Germ Cells ◽  
Model Organism ◽  
Vertebrate Model ◽  
The Stability ◽  
And Control ◽  
Asymmetrically Distributed ◽  
Cytoplasmic Determinants

Asymmetrically distributed cytoplasmic determinants collectively termed germ plasm have been shown to play an essential role in the development of primordial germ cells (PGCs). Here, we report the identification of a nanos-like (nanos1) gene, which is expressed in the germ plasm and in the PGCs of the zebrafish. We find that several mechanisms act in concert to restrict the activity of Nanos1 to the germ cells including RNA localization and control over the stability and translatability of the RNA. Reducing the level of Nanos1 in zebrafish embryos revealed an essential role for the protein in ensuring proper migration and survival of PGCs in this vertebrate model organism.

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.

The positional effect of presumptive primordial germ cells (pPGCs) on their differentiation into PGCs in Xenopus

Development ◽  
1988 ◽  
Vol 102 (3) ◽  
pp. 527-535
Author(s):  
K. Ikenishi ◽  
Y. Tsuzaki
Keyword(s):  
Germ Cells ◽  
Germ Plasm ◽  
Germ Line ◽  
Anterior Part ◽  
Primordial Germ Cells ◽  
Positional Effect ◽  
In Series

To determine whether the location of ‘germ plasm’-bearing cells [presumptive primordial germ cells (pPGCs)] is crucial for their differentiation into PGCs in Xenopus, [3H]thymidine-labelled pPGCs were implanted into the anterior or posterior halves of the endoderm in unlabelled host neurulae. Labelled PGCs in the genital ridges of experimental tadpoles were investigated by autoradiography. When the labelled pPGCs were implanted into posterior halves of the endoderm where host pPGCs are situated, 65 and 77% of the experimental tadpoles (designated as p-tadpoles) had the labelled PGCs in series I and II, respectively. When implanted into the anterior halves, 20 and 27% of the experimental tadpoles (a- tadpoles) had the labelled PGCs in series I and II, respectively. In p-tadpoles, the average numbers of labelled PGCs per tadpole were 8á7 in series I and 10 in series II, whereas they were 2á0 in a-tadpoles of both series. Both the proportion and the average number in p-tadpoles of both series were significantly different from those in a-tadpoles. In both series, labelled PGCs in p-tadpoles were found to be distributed throughout the genital ridges while those in a-tadpoles were localized only in the anterior part of the ridges. These facts indicate that the location of pPGCs in the endoderm affects their successful migration into the genital ridges, and that not only the presence of the germ plasm but also the proper location in endoderm are prerequisites to PGC differentiation of the germ line cells.

Partial characterization of ‘primordial germ cell-forming activity’ localized in vegetal pole cytoplasm in anuran eggs

Development ◽  
1977 ◽  
Vol 39 (1) ◽  
pp. 221-233
Author(s):  
Masami Wakahara
Keyword(s):  
Germ Cells ◽  
Germ Plasm ◽  
Primordial Germ Cells ◽  
Primordial Germ Cell ◽  
Differential Centrifugation ◽  
Rana Chensinensis ◽  
Crude Homogenate ◽  
Germinal Granules ◽  
Vegetal Pole

Larvae of Rana chensinensis developed from fertilized eggs which had been subjected to ultraviolet (u.v.) irradiation on their vegetal hemisphere at a dose of 20000 ergs/mm2 within 60 min of fertilization contained no primordial germ cells (PGCs) when examined histologically at the stage when the operculum was complete (8 days after fertilization at 18 °C, stage 25 according to Shumway, 1940). The morphogenetic ability of vegetal pole cytoplasm from non-irradiated eggs to establish the PGCs was tested by injecting some fractions of this cytoplasm into the vegetal hemisphere of u.v.-irradiated eggs. Crude homogenate of the vegetal pole cytoplasm without large yolk platelets was able to restore the PGCs when injected into u.v.-irradiated eggs, but a similar fraction from animal half cytoplasm had no ability to form PGCs. The ‘PGC-forming activity’ demonstrated in the crude homogenate of the vegetal pole cytoplasm was not abolished by dialysis, lyophilization and heating to 90 °C for 10 min. When the homogenate was fractionated by differential centrifugation in 0·25 M sucrose, the ‘PGC-forming activity’ was recovered mainly in the precipitate of 15000g for 30 min. The precipitate of 7000 g for 10 min had also a little ‘activity’. The possibility was discussed that the ‘PGC-forming activity’ demonstrated in the vegetal pole cytoplasm was associated with the germinal granules in the germ plasm rather than the mitochondria.

scholarly journals NUP50 is necessary for the survival of primordial germ cells in mouse embryos

Reproduction ◽  
2016 ◽  
Vol 151 (1) ◽  
pp. 51-58 ◽  
Author(s):  
Eunsook Park ◽  
Bobae Lee ◽  
Bruce E Clurman ◽  
Keesook Lee
Keyword(s):  
Embryonic Development ◽  
Germ Cells ◽  
Nuclear Pore Complex ◽  
Essential Role ◽  
Primordial Germ Cells ◽  
Mouse Embryos ◽  
Nuclear Pore ◽  
Progressive Loss ◽  
And Function ◽  
Deficient Mice

Nucleoporin 50 kDa (NUP50), a component of the nuclear pore complex, is highly expressed in male germ cells, but its role in germ cells is largely unknown. In this study, we analyzed the expression and function of NUP50 during the embryonic development of germ cells using NUP50-deficient mice. NUP50 was expressed in germ cells of both sexes at embryonic day 15.5 (E15.5), E13.5, and E12.5. In addition, NUP50 expression was also detected in primordial germ cells (PGCs) migrating into the genital ridges at E9.5. The gonads of Nup50−/− embryos of both sexes contained few PGCs at both E11.5 and E12.5 and no developing germ cells at E15.5. The migratory PGCs in Nup50−/− embryos at E9.5 showed increased apoptosis but a normal rate of proliferation, resulting in the progressive loss of germ cells at later stages. Taken together, these results suggest that NUP50 plays an essential role in the survival of PGCs during embryonic development.

scholarly journals A Drosophila toolkit for defining gene function in spermatogenesis

Reproduction ◽  
2017 ◽  
Vol 153 (4) ◽  
pp. R121-R132 ◽  
Author(s):  
N A Siddall ◽  
G R Hime
Keyword(s):  
Germ Cells ◽  
Gene Function ◽  
Primordial Germ Cells ◽  
Rapid Assessment ◽  
Model Organism ◽  
Time Frame ◽  
Individual Organism ◽  
Expression Of Genes ◽  
X Irradiation ◽  
Human Spermatogenesis

Expression profiling and genomic sequencing methods enable the accumulation of vast quantities of data that relate to the expression of genes during the maturation of male germ cells from primordial germ cells to spermatozoa and potential mutations that underlie male infertility. However, the determination of gene function in specific aspects of spermatogenesis or linking abnormal gene function with infertility remain rate limiting, as even in an era of CRISPR analysis of gene function in mammalian models, this still requires considerable resources and time. Comparative developmental biology studies have shown the remarkable conservation of spermatogenic developmental processes from insects to vertebrates and provide an avenue of rapid assessment of gene function to inform the potential roles of specific genes in rodent and human spermatogenesis. The vinegar fly, Drosophila melanogaster, has been used as a model organism for developmental genetic studies for over one hundred years, and research with this organism produced seminal findings such as the association of genes with chromosomes, the chromosomal basis for sexual identity, the mutagenic properties of X-irradiation and the isolation of the first tumour suppressor mutations. Drosophila researchers have developed an impressive array of sophisticated genetic techniques for analysis of gene function and genetic interactions. This review focuses on how these techniques can be utilised to study spermatogenesis in an organism with a generation time of 9 days and the capacity to introduce multiple mutant alleles into an individual organism in a relatively short time frame.

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