Germ Cells

Wylie, Chris

doi:10.1016/s0092-8674(00)80557-7

Cited by 367 publications

(188 citation statements)

References 112 publications

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“…However, the size and location of this body correspond to the yolk nucleus, a tight aggregate of membranes and vesicles within Balbiani's vitelline body, a poorly understood cytoplasmic complex (including a dense cloud of mitochondria, lamellar aggregates, and electrondense material) encompassing most of the ooplasm in species ranging from spiders to humans (22,32). The electron-dense material, which is intimately associated with and typically surrounds the yolk nucleus, corresponds to nuage, which in many species is asymmetrically distributed during embryogenesis and appears to play a determinative role in germ cell formation, whereby cells that inherit germ plasm are destined to become germ cells (1,2). A structure analogous to the yolk nucleus, termed the sponge body, has been described recently in Drosophila, and proposed to be involved in the assembly and transport of mRNAs such as bicoid in oocytes (33).…”

Section: Discussionmentioning

confidence: 99%

The human VASA gene is specifically expressed in the germ cell lineage

Castrillón

Quade

Wang

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

530

353

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To understand the origins and function of the human germ cell lineage and to identify germ cell-specific markers we have isolated a human ortholog of the Drosophila gene vasa. The gene was mapped to human chromosome 5q (near the centromere) by radiation hybrid mapping. We show by Northern analysis of fetal and adult tissues that expression of the human VASA gene is restricted to the ovary and testis and is undetectable in somatic tissues. We generated polyclonal antibodies that bind to the VASA protein in formalin-fixed, paraffin-embedded tissue and characterized VASA protein expression in human germ cells at various stages of development. The VASA protein is cytoplasmic and expressed in migratory primordial germ cells in the region of the gonadal ridge. VASA protein is present in fetal and adult gonadal germ cells in both males and females and is most abundant in spermatocytes and mature oocytes. The gene we have isolated is thus a highly specific marker of germ cells and should be useful for studies of human germ cell determination and function.gametogenesis ͉ DEAD box RNA helicase

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Section: Discussionmentioning

confidence: 99%

The human VASA gene is specifically expressed in the germ cell lineage

Castrillón

Quade

Wang

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

530

353

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“…Although high levels of conservation exists in body plan and axis formation across species, germ cell fate specification in mammals (at least in mice) appears to be unique in which maternally derived factors have not been shown to play any roles (1)(2)(3). Consistent with data of embryological studies that extraembryonic ectoderm signals the proximal epiblast to develop toward a PGC fate, genetic studies have revealed that BMP4 and BMP8B serve as the extraembryonic ectoderm-derived factors to induce PGCs (6-8, 19, 20).…”

Section: Discussionmentioning

confidence: 99%

“…Maternal factors play critical roles in germ cell specification in Drosophila, Caenorhabditis elegans, zebrafish, and frogs (1)(2)(3)(4)(5). By contrast, mice appear to use rather different developmental mechanisms.…”

mentioning

confidence: 99%

Induction of primordial germ cells from murine epiblasts by synergistic action of BMP4 and BMP8B signaling pathways

Ying

Qi²,

Zhao³

2001

Proc. Natl. Acad. Sci. U.S.A.

281

157

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Extraembryonic ectoderm-derived factors instruct the pluripotent epiblast cells to develop toward a restricted primordial germ cell (PGC) fate during murine gastrulation. Genes encoding Bmp4 of the Dpp class and Bmp8b of the 60A class are expressed in the extraembryonic ectoderm and targeted mutation of either results in severe defects in PGC formation. It has been shown that heterodimers of DPP and 60A classes of bone morphogenetic proteins (BMPs) are more potent than each homodimers in bone and mesoderm induction in vitro, suggesting that BMP4 and BMP8B may form heterodimers to induce PGCs. To investigate how BMP4 and BMP8B interact and signal for PGC induction, we cocultured epiblasts of embryonic day 6.0 -6.25 embryos with BMP4 and BMP8B proteins produced by COS cells. Our data show that BMP4 or BMP8B homodimers alone cannot induce PGCs whereas they can in combination, providing evidence that two BMP pathways are simultaneously required for the generation of a given cell type in mammals and also providing a prototype method for PGC induction in vitro. Furthermore, the PGC defects of Bmp8b mutants can be rescued by BMP8B homodimers whereas BMP4 homodimers cannot mitigate the PGC defects of Bmp4 null mutants, suggesting that BMP4 proteins are also required for epiblast cells to gain germ-line competency before the synergistic action of BMP4 and BMP8B.embryogenesis ͉ mouse ͉ stem cells ͉ cell fate determination P rimordial germ cells (PGCs) are progenitors of all gametes.Maternal factors play critical roles in germ cell specification in Drosophila, Caenorhabditis elegans, zebrafish, and frogs (1-5). By contrast, mice appear to use rather different developmental mechanisms. Embryological studies using lineage tracing by Lawson and Hage (6) revealed that proximal epiblast within one or two cell diameters of the extraembryonic ectoderm at embryonic day 6.0-6.5 (E6.0-6.5) eventually generated PGCs. Furthermore, descendents of a labeled cell in the proximal epiblast were found among PGCs and extraembryonic mesoderm cells (in particular the allantois), suggesting that the PGC fate is not fixed before E6.5 and PGCs and allantois share common precursors. Epiblast transplantation experiments showed that epiblast cells at different topological sites before E6.5 gave rise to PGCs only if they were positioned in close proximity to the extraembryonic ectoderm (7). Therefore, it was hypothesized that factors produced by the extraembryonic ectoderm are required for the generation of PGC precursors that eventually migrate toward the primitive streak and then segregate into PGC and allantois lineages. This hypothesis was further supported by epiblast cocultures with extraembryonic ectoderm (8).Bone morphogenetic proteins (BMPs) are members of the transforming growth factor type ␤ superfamily of growth factors that function as homodimers or heterodimers to signal through heteromeric receptor complexes and downstream SMAD proteins (9 -11). Although significant progress has been made in delineating their signal pathways in general...

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“…The precursors of the gametes are known as primordial germ cells (PGCs), and are morphologically similar in males and females. PGCs migrate from the hindgut endoderm to the mesoderm of the urogenital ridges to be incorporated into the future gonads (for review, see Wylie, 1999 Cell-cell interactions are known to be required for germ cell survival in embryonic and adult mice (Nocka et ah, 1989). Mouse PGCs will not migrate on plastic or purified extracellular matrix proteins, but will migrate on fibroblast feeder layers (Donovan et ah, 1986).…”

Section: Introductionmentioning

confidence: 99%