Germ cells are essential for sexual dimorphism in the medaka gonad

The study of mammalian meiosis is complicated by the timing of meiotic events in females and by the intermingling of meiotic sub-stages with somatic cells in the gonad of both sexes. In addition, studies of mouse mutants for different meiotic regulators have revealed significant differences in the stringency of meiotic events in males versus females. This sexual dimorphism implies that the processes of recombination and homologous chromosome pairing, while being controlled by similar genetic pathways, are subject to different levels of checkpoint control in males and females. This review is focused on the emerging picture of sexual dimorphism exhibited by mammalian germ cells using evidence from the broad range of meiotic mutants now available in the mouse. Many of these mouse mutants display distinct differences in meiotic progression and/or dysfunction in males versus females, and their continued study will allow us to understand the molecular basis for the sex-specific differences observed during prophase I progression.

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Germ cells are not essential for sexual dimorphism of gonads in common carp, C. carpio L.

Aquaculture ◽

10.1016/j.aquaculture.2021.737501 ◽

2022 ◽

Vol 547 ◽

pp. 737501

Author(s):

Binbin Tao ◽

Xianyao Liao ◽

Lu Chen ◽

Yongming Li ◽

Kuangxin Chen ◽

...

Keyword(s):

Sexual Dimorphism ◽

Common Carp ◽

Germ Cells

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Somatic sex-determining signals act on XX germ cells in Drosophila embryos

Development ◽

10.1242/dev.122.12.4065 ◽

1996 ◽

Vol 122 (12) ◽

pp. 4065-4071 ◽

Cited By ~ 11

Author(s):

S. Staab ◽

A. Heller ◽

M. Steinmann-Zwicky

Keyword(s):

Gene Expression ◽

Stem Cells ◽

Sexual Dimorphism ◽

Molecular Marker ◽

Germ Cells ◽

Specific Gene ◽

Male Germ Cells ◽

Enhancer Trap Line ◽

Trap Line ◽

Drosophila Embryos

In Drosophila, the enhancer-trap line mgm1 is already specifically expressed in male germ cells. Staining is first detected in 10-hour-old embryos and it is found in later stem cells. This line, which reveals the earliest sex-specific gene expression in the germline known so far, is a useful molecular marker to assess the sexual pathway that germ cells have entered before any overt sexual dimorphism is apparent. XY germ cells that develop in feminized animals express mgm1, which shows that this marker is autonomously expressed in XY germ cells. However, XX germ cells that develop in masculinized animals also express mgm1. Therefore, somatic sex-determining signals have already acted on XX germ cells in 10-hour-old embryos.

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Gpbox (Psx2), a Homeobox Gene Preferentially Expressed in Female Germ Cells at the Onset of Sexual Dimorphism in Mice

Developmental Biology ◽

10.1006/dbio.2000.9741 ◽

2000 ◽

Vol 223 (1) ◽

pp. 181-193 ◽

Cited By ~ 24

Author(s):

Nobuyoshi Takasaki ◽

Robert McIsaac ◽

Jurrien Dean

Keyword(s):

Sexual Dimorphism ◽

Germ Cells ◽

Homeobox Gene

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Normal Gonadal Development in Mice Lacking GPBOX, a Homeobox Protein Expressed in Germ Cells at the Onset of Sexual Dimorphism

Molecular and Cellular Biology ◽

10.1128/mcb.21.23.8197-8202.2001 ◽

2001 ◽

Vol 21 (23) ◽

pp. 8197-8202 ◽

Cited By ~ 21

Author(s):

Nobuyoshi Takasaki ◽

Tracy Rankin ◽

Jurrien Dean

Keyword(s):

Sexual Dimorphism ◽

Germ Cells ◽

Embryonic Stem ◽

Homeobox Gene ◽

Mouse Cell ◽

Gonadal Development ◽

Targeted Mutagenesis ◽

Embryonic Gonad ◽

The Family ◽

Homeobox Protein

ABSTRACT Gpbox is a paired-like homeobox gene that colocalizes with two other members of the family, PsxI andPem, on the proximal portion of the mouse X chromosome.Gpbox is expressed in the extraembryonic placenta and within the germ cells of the embryonic gonad. Beginning with the onset of sexual dimorphism (embryonic day [E]11.5 to 12.5), GPBOX transcripts accumulate faster in female than in male germ cells but disappear later in embryogenesis (E16) and have not been reported in adult tissues. To investigate the function of Gpbox, mouse cell lines lacking GPBOX were established using targeted mutagenesis in embryonic stem cells. Both homozygous Gpbox null female and hemizygous Gpbox null male mice were fertile and reproduced normally. Additionally, the development of male and female gonads in the null background was indistinguishable from that observed in normal littermates. The lack of an obvious phenotype raises the possibility that another member of this homeobox gene family provides the absentGpbox function.

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Freeze-etch observations on the tight junctions of sertoli cells grown in organ culture with FSH

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010008256x ◽

1978 ◽

Vol 36 (2) ◽

pp. 340-341

Author(s):

Rita Meyer ◽

Zoltan Posalaky ◽

Dennis Mcginley

Keyword(s):

Organ Culture ◽

Tight Junctions ◽

Sertoli Cell ◽

Germ Cells ◽

Sertoli Cells ◽

Barrier Function ◽

Cell Junction ◽

Intramembranous Particles ◽

Junctional Complexes ◽

Oriented Parallel

The Sertoli cell tight junctional complexes have been shown to be the most important structural counterpart of the physiological blood-testis barrier. In freeze etch replicas they consist of extensive rows of intramembranous particles which are not only oriented parallel to one another, but to the myoid layer as well. Thus the occluding complex has both an internal and an overall orientation. However, this overall orientation to the myoid layer does not seem to be necessary to its barrier function. The 20 day old rat has extensive parallel tight junctions which are not oriented with respect to the myoid layer, and yet they are inpenetrable by lanthanum. The mechanism(s) for the control of Sertoli cell junction development and orientation has not been established, although such factors as the presence or absence of germ cells, and/or hormones, especially FSH have been implicated.

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Comparative Morphology of Intercellular Bridges Between Developing Germ Cells of the Ovary

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100068631 ◽

1970 ◽

Vol 28 ◽

pp. 328-329

Author(s):

J. R. Ruby ◽

R. F. Dyer ◽

R. G. Skalko ◽

R. F. Gasser ◽

E. P. Volpe

Keyword(s):

Germ Cells ◽

Rana Pipiens ◽

Comparative Morphology ◽

Dense Material ◽

Individual Species ◽

Microscope Examination ◽

Electron Dense Material ◽

Intercellular Bridges ◽

Cytoplasmic Side ◽

Intercellular Connections

An electron microscope examination of fetal ovaries has revealed that developing germ cells are connected by intercellular bridges. In this investigation several species have been studied including human, mouse, chicken, and tadpole (Rana pipiens). These studies demonstrate that intercellular connections are similar in morphology regardless of the species.Basically, all bridges are characterized by a band of electron-dense material on the cytoplasmic side of the tri-laminar membrane surrounding the connection (Fig.l). This membrane is continuous with the plasma membrane of the conjoined cells. The dense material, however, never extends beyond the limits of the bridge. Variations in the configuration of intercellular connections were noted in all ovaries studied. However, the bridges in each individual species usually exhibits one structural characteristic seldom found in the others. For example, bridges in the human ovary very often have large blebs projecting from the lateral borders whereas the sides of the connections in the mouse gonad merely demonstrate a slight convexity.

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Hexachlorobenzene toxicity in the rat ovary: II. Ultrastructure induced by medium (10 mg/kg) dose exposure

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010012374x ◽

1992 ◽

Vol 50 (1) ◽

pp. 668-669

Author(s):

Amreek Singh ◽

Warren G. Foster ◽

Anna Dykeman ◽

David C. Villeneuve

Keyword(s):

Germ Cells ◽

Primordial Germ Cells ◽

Surface Epithelium ◽

Morphological Parameters ◽

Comprehensive Investigation ◽

Ovary Surface Epithelium ◽

Rat Ovary ◽

High Doses

Hexachlorobenzene (HCB) is a known toxicant that is found in the environment as a by-product during manufacture of certain pesticides. This chlorinated chemical has been isolated from many tissues including ovary. When administered in high doses, HCB causes degeneration of primordial germ cells and ovary surface epithelium in sub-human primates. A purpose of this experiment was to determine a no-effect dose of the chemical on the rat ovary. The study is part of a comprehensive investigation on the effects of the compound on the biochemical, hematological, and morphological parameters in the monkey and rat.

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Electron microscope study of the effects of radiation on insect fertility

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100157905 ◽

1990 ◽

Vol 48 (3) ◽

pp. 72-73

Author(s):

Judy Ju-Hu Chiang ◽

Robert Kuo-Cheng Chen

Keyword(s):

Electron Microscopy ◽

Germ Cell ◽

Germ Cells ◽

Electron Microscope Study ◽

Radiation Treatment ◽

Light And Electron Microscopy ◽

Stem Borer ◽

Metabolic Energy ◽

Rice Stem Borer ◽

Effects Of Radiation

Germ cells from the rice stem borer Chilo suppresalis, were examined by light and electron microscopy. Damages to organelles within the germ cells were observed. The mitochondria, which provide the cell with metabolic energy, were seen to disintegrate within the germ cell. Lysosomes within the germ cell were also seen to disintegrate. The subsequent release of hydrolytic enzymesmay be responsible for the destruction of organelles within the germ cell. Insect spermatozoa were seen to lose the ability to move because of radiation treatment. Damage to the centrioles, one of which is in contact with the tail, may be involved in causing sperm immobility.

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