Germ cell migration in toad (Bufo bufo): effect of ventral grafting of embryonic dorsal regions

Development ◽  
1974 ◽  
Vol 31 (1) ◽  
pp. 75-87
Author(s):  
Piero P. Giorgi

Bufo bufo embryos were used at the tail-bud stage for the grafting of two different dorsal regions (cephalic and caudal tracts) into the ventral side of the embryo (cf. Fig. 1). Germ cell localization was studied at the beginning of larval life. The results seem to confirm the original finding of Gipouloux (1970) who suggested that in anurans germ cells migrate under the attraction of a substance produced by the dorsal mesodermal tissues. The attractive action of dorsal tissue was confined to the caudal region of the embryo. In operated specimens the migration of germ cells was drastically altered. The genital ridges of host embryos were almost sterile, while numerous germ cells appeared associated with caudal grafts. A considerably smaller number of germ cells was associated with cephalic grafts. About 80% of germ cells associated with caudal grafts were present at the same levels where a well-developed dorsal mesentery was also present. It is suggested that the formation of the dorsal mesentery plays a morphogenetic role in segregating primordial germ cells from other endodermal cells and contributes to their final localization in the genital ridges.

2005 ◽  
Vol 17 (5) ◽  
pp. 587 ◽  
Author(s):  
Yixiang Zhang ◽  
Xiumei Jin ◽  
Haitang Han ◽  
Zandong Li

Polychlorinated biphenyls cause developmental and physiological anomalies in the reproductive system. This study investigated the effects of 2,2′,5,5′-tetrachlorobiphenyl (PCB52), which can produce oestrogenic effects on the homeostasis of chicken primordial germ cells from the initial stage until completion of their settlement in the gonadal primordium. The blastoderm of chicken embryos was injected with 1 μL PCB52 (10 µmol/L) and oestradiol (100 µmol/L) before incubation, and the number of primordial germ cells was determined during their migration and development. The number of primordial germ cells in germinal crescents in PCB52-treated groups was slightly decreased (P = 0.068), but it was reduced significantly at stages 13–15 and 28–30 (P < 0.01, respectively) compared with controls. No obvious effects on primordial germ cell migration were observed with oestradiol treatments. The present results suggest that the influence of PCB52 on chicken primordial germ cell migration and proliferation may be via its toxic effect, not its oestrogen-mimicking effect, and provide information on the sensitivity of primordial germ cells to the direct action of PCB52.


Development ◽  
1999 ◽  
Vol 126 (8) ◽  
pp. 1655-1664 ◽  
Author(s):  
R. Anderson ◽  
R. Fassler ◽  
E. Georges-Labouesse ◽  
R.O. Hynes ◽  
B.L. Bader ◽  
...  

Primordial germ cells are the founder cells of the gametes. They are set aside at the initial stages of gastrulation in mammals, become embedded in the hind-gut endoderm, then actively migrate to the sites of gonad formation. The molecular basis of this migration is poorly understood. Here we sought to determine if members of the integrin family of cell surface receptors are required for primordial germ cell migration, as integrins have been implicated in the migration of several other motile cell types. We have established a line of mice which express green fluorescent protein in germline cells that has enabled us to efficiently purify primordial germ cells at different stages by flow cytometry. We have catalogued the spectrum of integrin subunit expression by primordial germ cells during and after migration, using flow cytometry, immunocytochemistry and RT-PCR. Through analysis of integrin beta1(−/−)--&gt;wild-type chimeras, we show that embryonic cells lacking beta1 integrins can enter the germline. However, integrin beta1(−/−) primordial germ cells do not colonize the gonad efficiently. Embryos with targeted deletion of integrin subunit alpha3, alpha6, or alphaV show no major defects in primordial germ cell migration. These results demonstrate a role for beta1-containing integrins in the development of the germline, although an equivalent role for * integrin subunit(s) has yet to be established.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jonathan J. Carver ◽  
Yuanfa He ◽  
Yong Zhu

AbstractAdamts9 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 9) is one of a few metalloproteinases structurally conserved from C. elegans to humans and is indispensable in germ cell migration in invertebrates. However, adamts9′s roles in germ cell migration in vertebrates has not been examined. In the present study, we found zygotic expression of adamts9 started around the germ ring stage and reached peak levels at 3 days post fertilization (dpf) in zebrafish. The migration of primordial germ cells (PGC) was completed within 24 hours (h) in wildtype siblings, while a delay in PGC migration was found at 15 and 24-h post-fertilization (hpf) in the Adamts9 knockout (KO). However, the delayed PGC migration in Adamts9 KO disappeared at 48 hpf. Our study suggests a conserved function of Adamts9 in germ cell migration among invertebrates and vertebrates. In addition, our results also suggest that Adamts9 is not essential for germ cell migration as reported in C. elegans, possibly due to expansion of Adamts family members and compensatory roles from other metalloproteinases in vertebrates. Further studies are required in order to elucidate the functions and mechanisms of metalloproteinases in germ cell migration and gonad formation in vertebrates.


Development ◽  
1994 ◽  
Vol 120 (1) ◽  
pp. 83-89 ◽  
Author(s):  
M.K. Jaglarz ◽  
K.R. Howard

In Drosophila, as in many other organisms, primordial germ cells show invasive and migratory behavior moving from their site of origin to the somatic component of the gonad. At a characteristic time in development, the primordial germ cells pass across the primordium of the gut and migrate on its outer surface toward the mesoderm, where they eventually associate with the somatic tissues of the gonad. Here we demonstrate that the exit and migration are specific behaviors of the primordial germ cells and that they are controlled by the somatic tissue of the embryo rather than by a germ cell autonomous clock. Using mutations, we show that these controlling somatic events probably occur in the tissue of the gut primordium itself.


Development ◽  
1998 ◽  
Vol 125 (4) ◽  
pp. 655-666 ◽  
Author(s):  
H.T. Broihier ◽  
L.A. Moore ◽  
M. Van Doren ◽  
S. Newman ◽  
R. Lehmann

In Drosophila as well as many vertebrate systems, germ cells form extraembryonically and migrate into the embryo before navigating toward gonadal mesodermal cells. How the gonadal mesoderm attracts migratory germ cells is not understood in any system. We have taken a genetic approach to identify genes required for germ cell migration in Drosophila. Here we describe the role of zfh-1 in germ cell migration to the gonadal mesoderm. In zfh-1 mutant embryos, the initial association of germ cells and gonadal mesoderm is blocked. Loss of zfh-1 activity disrupts the development of two distinct mesodermal populations: the caudal visceral mesoderm and the gonadal mesoderm. We demonstrate that the caudal visceral mesoderm facilitates the migration of germ cells from the endoderm to the mesoderm. Zfh-1 is also expressed in the gonadal mesoderm throughout the development of this tissue. Ectopic expression of Zfh-1 is sufficient to induce additional gonadal mesodermal cells and to alter the temporal course of gene expression within these cells. Finally, through analysis of a tinman zfh-1 double mutant, we show that zfh-1 acts in conjunction with tinman, another homeodomain protein, in the specification of lateral mesodermal derivatives, including the gonadal mesoderm.


Author(s):  
Arend W. Overeem ◽  
Yolanda W. Chang ◽  
Jeroen Spruit ◽  
Celine M. Roelse ◽  
Susana M. Chuva De Sousa Lopes

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.


2018 ◽  
Author(s):  
Kathryn E. Kistler ◽  
Tatjana Trcek ◽  
Thomas R. Hurd ◽  
Ruoyu Chen ◽  
Feng-Xia Liang ◽  
...  

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.


2008 ◽  
Vol 78 (Suppl_1) ◽  
pp. 64-64
Author(s):  
Jillian Guttormsen ◽  
Gerrit J. Bouma ◽  
Frances Bhushan ◽  
Trevor Williams ◽  
Quinton A. Winger

Development ◽  
1985 ◽  
Vol 90 (1) ◽  
pp. 79-99
Author(s):  
J. H. Cleine ◽  
K. E. Dixon

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.


Development ◽  
1976 ◽  
Vol 35 (3) ◽  
pp. 607-616
Author(s):  
W. J. Gehring ◽  
E. Wieschaus ◽  
M. Holliger

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.


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