Unscrambling the oocyte and the egg: clarifying terminology of the female gamete in mammals

Abstract Most reproductive biologists who study female gametes will agree with the 16th century anatomist William Harvey’s doctrine: ‘Ex Ovo Omnia’. This phrase, which literally translates to ‘everything from the egg’, recognizes the centrality of the egg in animal development. Eggs are most impressive cells, capable of supporting development of an entirely new organism following fertilization or parthenogenetic activation. Not so uniformly embraced in the field of reproductive biology is the nomenclature used to refer to the female germ cell. What is an oocyte? What is an egg? Are these terms the same, different, interchangeable? Here we provide functional definitions of the oocyte and egg, and how they can be used in the context of mammalian gamete biology and beyond.

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Memoirs: The Cytopasmic Inclusion of the Germ-Cells

Journal of Cell Science ◽

10.1242/jcs.s2-62.247.407 ◽

1917 ◽

Vol s2-62 (247) ◽

pp. 407-463

Author(s):

J. BRONTÉ GATENBY

Keyword(s):

Germ Cell ◽

Primordial Germ Cell ◽

Growth Period ◽

Pieris Brassicae ◽

Constant Factor ◽

Cytoplasmic Bodies ◽

Female Germ Cell ◽

Probable Nature ◽

And Function ◽

Definite Period

(1) In Smerinthus populi, Pieris brassicæ, and a number of other species of moths and butterflies the cytoplasmic bodies have been followed out. (2) The micromitosome lias been followed from the spermatocyte back into the secondary spermatogonium. It is very probably present in the primordial germ-cell. (3) The micromitosome has been definitely found in the female. (4) The micromitosome seems to divide in all divisions, and I consider that it is a constant factor in the spermatids of Smerinthus. (5) The probable nature and function of the micromitosome is discussed. (6) The mitochondria have been carefully examined in the male and female germ-cell in all stages except in the maturation division of the female and in fertilisation. (7) It has been shown that in early stages the cytoplasmic bodies of the female resemble those of the male. (8) There is a definite period, judged to be about the beginning of growth stage, when the subsequent fate of the mitochondria in the male becomes different from that of the female. (9) The remarkable formation of chromophobe and chromophile zones in the male mitochondrial body aud the use of these zones are described. (10) The formation of the macromitosome from the mitochondria is described. (11) The changes undergone by the macromitosome in sperm formation are followed out. (12) The presence of the acroblasts in the fairly early growth period of the spermatocyte is described. (13) The complicated evolutions of these bodies in division of the cells, their subsequent fate and' their probable nature are discussed. (14) The staining and fixing reactions of the cytoplasmic bodies are fully described. (15) A number of abnormalities have been described. (16) The centrosome has been shown to divide in the young spermatid, and one centrosome is probably lost, but definite evidence is not forthcoming.

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Molecular signatures to define spermatogenic cells in common marmoset (Callithrix jacchus)

Reproduction ◽

10.1530/rep-11-0215 ◽

2012 ◽

Vol 143 (5) ◽

pp. 597-609 ◽

Cited By ~ 15

Author(s):

Zachary Yu-Ching Lin ◽

Masanori Imamura ◽

Chiaki Sano ◽

Ryusuke Nakajima ◽

Tomoko Suzuki ◽

...

Keyword(s):

Germ Cell ◽

Reproductive Biology ◽

Germ Cells ◽

Methylation Status ◽

Common Marmoset ◽

Methylation Pattern ◽

Callithrix Jacchus ◽

Molecular Signatures ◽

Spermatogenic Cells ◽

Human Reproductive

Germ cell development is a fundamental process required to produce offspring. The developmental program of spermatogenesis has been assumed to be similar among mammals. However, recent studies have revealed differences in the molecular properties of primate germ cells compared with the well-characterized mouse germ cells. This may prevent simple application of rodent insights into higher primates. Therefore, thorough investigation of primate germ cells is necessary, as this may lead to the development of more appropriate animal models. The aim of this study is to define molecular signatures of spermatogenic cells in the common marmoset, Callithrix jacchus. Interestingly, NANOG, PRDM1, DPPA3 (STELLA), IFITM3, and ZP1 transcripts, but no POU5F1 (OCT4), were detected in adult marmoset testis. Conversely, mouse testis expressed Pou5f1 but not Nanog, Prdm1, Dppa3, Ifitm3, and Zp1. Other previously described mouse germ cell markers were conserved in marmoset and mouse testes. Intriguingly, marmoset spermatogenic cells underwent dynamic protein expression in a developmental stage-specific manner; DDX4 (VASA) protein was present in gonocytes, diminished in spermatogonial cells, and reexpressed in spermatocytes. To investigate epigenetic differences between adult marmoset and mice, DNA methylation analyses identified unique epigenetic profiles to marmoset and mice. Marmoset NANOG and POU5F1 promoters in spermatogenic cells exhibited a methylation status opposite to that in mice, while the DDX4 and LEFTY1 loci, as well as imprinted genes, displayed an evolutionarily conserved methylation pattern. Marmosets have great advantages as models for human reproductive biology and are also valuable as experimental nonhuman primates; thus, the current study provides an important platform for primate reproductive biology, including possible applications to humans.

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Notch pathway regulates female germ cell meiosis progression and early oogenesis events in fetal mouse

Cell Cycle ◽

10.4161/cc.27708 ◽

2014 ◽

Vol 13 (5) ◽

pp. 782-791 ◽

Cited By ~ 32

Author(s):

Yan-Min Feng ◽

Gui-Jin Liang ◽

Bo Pan ◽

XunSi Qin ◽

Xi-Feng Zhang ◽

...

Keyword(s):

Germ Cell ◽

Notch Pathway ◽

Fetal Mouse ◽

Female Germ Cell

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Society for Reproductive Biology Founders' Lecture 2007. Insights into germ cell biology: from the bench to the clinic

Reproduction Fertility and Development ◽

10.1071/rd07090 ◽

2007 ◽

Vol 19 (7) ◽

pp. 783 ◽

Cited By ~ 1

Author(s):

Angshumoy Roy ◽

Martin M. Matzuk

Keyword(s):

Germ Cell ◽

Cell Biology ◽

Transforming Growth Factor ◽

Transforming Growth Factor Β ◽

Signalling Pathways ◽

Male And Female ◽

Paracrine Signalling ◽

Fertility Clinic ◽

Female Germ Cell

The germline is unique among tissues in being the only lineage that is transmitted through generations. The gonadal somatic cells that interact with male and female germ cells are equally important for their juxtacrine and paracrine signalling pathways that lead to the formation of functionally mature gametes and healthy progeny. The present review summarises exciting new studies that our group and others have achieved at the frontier of male and female germ cell biology and in studying transforming growth factor-β signalling pathways in oocyte–somatic cell interactions and gonadal growth and differentiation. In the process, we have produced over 70 transgenic and knockout models to study reproduction in vivo. These models have helped us identify novel and unexplored areas of germ cell biology and translate this work into the fertility clinic.

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Structure of the germarium and female germ-cell clusters in Thulinius ruffoi (Bertolani, 1982) (Tardigrada: Eutardigrada: Parachela)

Zoological Journal of the Linnean Society ◽

10.1093/zoolinnean/zlz108 ◽

2019 ◽

Author(s):

Kamil Janelt ◽

Marta Jezierska ◽

Sebastian Student ◽

Izabela Poprawa

Keyword(s):

Germ Cell ◽

Laser Scanning ◽

Spatial Organization ◽

Germ Line ◽

Anterior Part ◽

Confocal Laser ◽

Freshwater Species ◽

Cell Clusters ◽

Scanning Transmission ◽

Female Germ Cell

Abstract Thulinius ruffoi is a freshwater species that has the ability to reproduce via parthenogenesis. A meroistic polytrophic ovary is present in this species. Analyses of the germarium structure, and formation and organization of female germ-cell clusters were performed using light, confocal laser scanning, transmission electron and serial block-face scanning electron microscopy. The germarium is the small, anterior part of an ovary that contains putative germ-line stem cells. In the studied species, the female germ-cell clusters are large and branched. Only one cell in each cluster develops into an oocyte, while all the other cells become trophocytes. In this paper, we present the ﬁrst report on the presence of F-actin as a component of the intercellular bridges that connect the cells in the germ-cell cluster of T. ruffoi. Moreover, our results show that the female germ-cell clusters are formed as the result of both synchronous and asynchronous divisions and that their organization can vary not only between individuals of the investigated species, but also that clusters developing simultaneously within the same ovary can have a different spatial organization.

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