scholarly journals Mouse Ovarian Germ Cell Cysts Undergo Programmed Breakdown to Form Primordial Follicles

2001 ◽  
Vol 234 (2) ◽  
pp. 339-351 ◽  
Author(s):  
Melissa E. Pepling ◽  
Allan C. Spradling
Keyword(s):  
Germ Cell ◽  
Primordial Follicles ◽  
Germ Cell Cysts

scholarly journals Mouse oocytes within germ cell cysts and primordial follicles contain a Balbiani body

2006 ◽  
Vol 104 (1) ◽  
pp. 187-192 ◽  
Author(s):  
M. E. Pepling ◽  
J. E. Wilhelm ◽  
A. L. O'Hara ◽  
G. W. Gephardt ◽  
A. C. Spradling
Keyword(s):  
Germ Cell ◽  
Primordial Follicles ◽  
Balbiani Body ◽  
Mouse Oocytes ◽  
Germ Cell Cysts

scholarly journals Follistatin Regulates Germ Cell Nest Breakdown and Primordial Follicle Formation

Endocrinology ◽  
2010 ◽  
Vol 152 (2) ◽  
pp. 697-706 ◽  
Author(s):  
Fuminori Kimura ◽  
Lara M. Bonomi ◽  
Alan L. Schneyer
Keyword(s):  
Germ Cell ◽  
Germ Cells ◽  
Ovarian Function ◽  
Primordial Follicle ◽  
Biochemical Properties ◽  
The Body ◽  
Protein Isoforms ◽  
Primordial Follicles ◽  
Reduced Rate ◽  
Regulatory Functions

Abstract Follistatin (FST) is an antagonist of activin and related TGFβ superfamily members that has important reproductive actions as well as critical regulatory functions in other tissues and systems. FST is produced as three protein isoforms that differ in their biochemical properties and in their localization within the body. We created FST288-only mice that only express the short FST288 isoform and previously reported that females are subfertile, but have an excess of primordial follicles on postnatal day (PND) 8.5 that undergo accelerated demise in adults. We have now examined germ cell nest breakdown and primordial follicle formation in the critical PND 0.5–8.5 period to test the hypothesis that the excess primordial follicles derive from increased proliferation and decreased apoptosis during germ cell nest breakdown. Using double immunofluorescence microscopy we found that there is virtually no germ cell proliferation after birth in wild-type or FST288-only females. However, the entire process of germ cell nest breakdown was extended in time (through at least PND 8.5) and apoptosis was significantly reduced in FST288-only females. In addition, FST288-only females are born with more germ cells within the nests. Thus, the excess primordial follicles in FST288-only mice derive from a greater number of germ cells at birth as well as a reduced rate of apoptosis during nest breakdown. These results also demonstrate that FST is critical for normal regulation of germ cell nest breakdown and that loss of the FST303 and/or FST315 isoforms leads to excess primordial follicles with accelerated demise, resulting in premature cessation of ovarian function.

scholarly journals BAX regulates follicular endowment in mice

Reproduction ◽  
2007 ◽  
Vol 133 (5) ◽  
pp. 865-876 ◽  
Author(s):  
Chuck R Greenfeld ◽  
Melissa E Pepling ◽  
Janice K Babus ◽  
Priscilla A Furth ◽  
Jodi A Flaws
Keyword(s):  
Cell Viability ◽  
Germ Cell ◽  
Proliferative Activity ◽  
Primordial Germ Cell ◽  
Initial Endowment ◽  
Regulatory Activity ◽  
Wild Type ◽  
X Protein ◽  
Primordial Follicles

It is believed that the endowment of primordial follicles in mammalian ovaries is finite. Once follicles are depleted, infertility ensues. Thus, the size of the initial endowment has consequences for fertility and reproductive longevity. Follicular endowment is comprised of various processes that culminate with the incorporation of meiosis-arrested oocytes into primordial follicles. Apoptosis is prominent during follicular endowment, and apoptosis regulatory genes are involved in its regulation. Conflicting data exist with regard to the role of the proapoptotic Bcl-2 associated X protein (BAX) in follicular endowment. Therefore, we investigated the role of BAX during follicular endowment in embryonic and neonatal ovaries. We found that BAX is involved in regulating follicular endowment in mice. Deletion ofBaxyields increased oocyte numbers in embryonic ovaries and increased follicle numbers in neonatal ovaries when compared with wild-type ovaries. Increased follicular endowment inBax−/−ovaries is not due to enhanced germ cell viability. Further, it is not due to an increased primordial germ cell (PGC) allotment, a delay in the onset of meiosis, or altered proliferative activity of oogonia. Instead, our data suggest that the regulatory activity of BAX in follicular endowment likely occurs during PGC migration, prior to PGC colonization of the gonad.

scholarly journals Follicular assembly: mechanisms of action

Reproduction ◽  
2012 ◽  
Vol 143 (2) ◽  
pp. 139-149 ◽  
Author(s):  
Melissa E Pepling
Keyword(s):  
Cell Death ◽  
Germ Line ◽  
Primordial Germ Cells ◽  
Primordial Follicle ◽  
Mechanisms Of Action ◽  
Initial Number ◽  
Primordial Follicles ◽  
Meiotic Progression ◽  
Germ Cell Cysts ◽  
Reproductive Cancers

The differentiation of primordial germ cells (PGCs) into functional oocytes is important for the continuation of species. In mammals, PGCs begin to differentiate into oocytes during embryonic development. Oocytes develop in clusters called germ line cysts. During fetal or neonatal development, germ cell cysts break apart into single oocytes that become surrounded by pregranulosa cells to form primordial follicles. During the process of cyst breakdown, a subset of cells in each cyst undergoes cell death with only one-third of the initial number of oocytes surviving to form primordial follicles. The mechanisms that control cyst breakdown, oocyte survival, and follicle assembly are currently under investigation. This review describes the mechanisms that have been implicated in the control of primordial follicle formation, which include programmed cell death regulation, growth factor and other signaling pathways, regulation by transcription factors and hormones, meiotic progression, and changes in cell adhesion. Elucidation of mechanisms leading to formation of the primordial follicle pool will help research efforts in ovarian biology and improve treatments of female infertility, premature ovarian failure, and reproductive cancers.

scholarly journals The dynamics of the primordial follicle reserve

Reproduction ◽  
2013 ◽  
Vol 146 (6) ◽  
pp. R205-R215 ◽  
Author(s):  
Jeffrey B Kerr ◽  
Michelle Myers ◽  
Richard A Anderson
Keyword(s):  
Germ Cell ◽  
Large Scale ◽  
Indirect Evidence ◽  
Primordial Follicle ◽  
Genetically Engineered ◽  
Postnatal Life ◽  
Cell Dynamics ◽  
Primordial Follicles ◽  
Age Related ◽  
Female Germline

The female germline comprises a reserve population of primordial (non-growing) follicles containing diplotene oocytes arrested in the first meiotic prophase. By convention, the reserve is established when all individual oocytes are enclosed by granulosa cells. This commonly occurs prior to or around birth, according to species. Histologically, the ‘reserve’ is the number of primordial follicles in the ovary at any given age and is ultimately depleted by degeneration and progression through folliculogenesis until exhausted. How and when the reserve reaches its peak number of follicles is determined by ovarian morphogenesis and germ cell dynamics involving i) oogonial proliferation and entry into meiosis producing an oversupply of oocytes and ii) large-scale germ cell death resulting in markedly reduced numbers surviving as the primordial follicle reserve. Our understanding of the processes maintaining the reserve comes primarily from genetically engineered mouse models, experimental activation or destruction of oocytes, and quantitative histological analysis. As the source of ovulated oocytes in postnatal life, the primordial follicle reserve requires regulation of i) its survival or maintenance, ii) suppression of development (dormancy), and iii) activation for growth and entry into folliculogenesis. The mechanisms influencing these alternate and complex inter-related phenomena remain to be fully elucidated. Drawing upon direct and indirect evidence, we discuss the controversial concept of postnatal oogenesis. This posits a rare population of oogonial stem cells that contribute new oocytes to partially compensate for the age-related decline in the primordial follicle reserve.

Expression of Bcl-2 and 3-ß hydroxysteroid dehydrogenase protein during oocyte and follicle development in fetal and post-natal pig ovaries

1999 ◽  
Vol 11 (8) ◽  
pp. 463 ◽  
Author(s):  
Wesley M. Garrett ◽  
H. David Guthrie
Keyword(s):  
Cell Proliferation ◽  
Germ Cell ◽  
Germ Cells ◽  
Granulosa Cells ◽  
Stromal Cells ◽  
Post Partum ◽  
Nuclear Antigen ◽  
Ki 67 ◽  
Primordial Follicles ◽  
Small Clusters

The fetal and post-natal development of the pig ovary involves both proliferation and apoptotic loss of germ cells, follicle formation and growth, and the initiation of oocyte meiotic maturation. The present study measured the expression of the proto-oncogene Bcl-2 immunohistochemically on paraffin sections of pig ovaries to determine its relationship with folliculogenesis on Days 50 and 80 post coitum (p.c.) and on Days 1, 21, and 56 post partum (p.p.). The expression of the steroidogenic enzyme 3β-hydroxy-steroid dehydrogenase (3βHSD) was used to determine the lineages of the cells forming the ovarian follicles, and the expression of the cell proliferation-associated nuclear antigen Ki-67 was used to determine germ cell proliferation and the initiation of follicle growth. Expression of Ki-67 showed that many oogonia were proliferating on Days 50 and 80 p.c. Granulosa cells were more proliferative on Day 56 p.p. than at any other stage; Ki-67 was expressed in 70% of growing follicles and granulosa cells had a 3% mean staining index per section. Less than 4% of germ cells and follicles had morphological signs of degeneration during the period of the study. Bcl-2 was most abundant on Days 21 p.p. and 56 p.p.; staining was localized to stromal cells among follicles and in small clusters in the cortical–medullary junction (CMJ). 3βHSD staining on Day 50 p.c. was seen in cords of stromal cells within the medulla of the ovary, and in the stromal cells investing the oogonial nests. On Days 80 p.c., 1 p.p., 21 p.p., and 56 p.p., 3βHSD was expressed in the granulosa cells of primary or primordial follicles at the CMJ. Production of Bcl-2 by somatic cells may support germ cell and preantral follicle survival.

scholarly journals Early oogenesis in the short-tailed fruit bat Carollia perspicillata: Transient germ cell cysts and noncanonical intercellular bridges

genesis ◽  
2011 ◽  
Vol 50 (1) ◽  
pp. 18-27 ◽  
Author(s):  
Agnieszka Lechowska ◽  
Szczepan M. Bilinski ◽  
John J. Rasweiler ◽  
Chris J. Cretekos ◽  
Richard R. Behringer ◽  
...  
Keyword(s):  
Germ Cell ◽  
Carollia Perspicillata ◽  
Intercellular Bridges ◽  
Fruit Bat ◽  
Germ Cell Cysts

scholarly journals Germ cell cysts and simultaneous sperm and oocyte production in a hermaphroditic nematode

2017 ◽  
Vol 430 (2) ◽  
pp. 362-373 ◽  
Author(s):  
Caitlin M. McCaig ◽  
Xiaoxue Lin ◽  
Maureen Farrell ◽  
Kathryn Rehain-Bell ◽  
Diane C. Shakes
Keyword(s):  
Germ Cell ◽  
Germ Cell Cysts
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