Germ cell kinetics during early ovarian differentiation: An analysis of the oogonial cell cycle and the subsequent changes in oocyte development during the onset of meiosis in the rat

Wartenberg, H.; Hilscher, B.; Hilscher, W

doi:10.1002/(sici)1097-0029(19980301)40:5<377::aid-jemt5>3.0.co;2-o

Cited by 21 publications

(5 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The existence of two waves of pachytene oocytes in B6CBF2 mice is consistent with other data from our group (unpublished) and could be a genetic effect [36,37]. Biphasic observations of prenatal oocyte degeneration and the premeiotic S phase have been reported in rats [30,38]. …”

Section: Resultssupporting

confidence: 91%

Apoptosis in mouse fetal and neonatal oocytes during meiotic prophase one

2007

View full text Add to dashboard Cite

Background: The vast majority of oocytes formed in the fetal ovary do not survive beyond birth. Possible reasons for their loss include the elimination of non-viable genetic constitutions arising through meiosis, however, the precise relationship between meiotic stages and prenatal apoptosis of oocytes remains elusive. We studied oocytes in mouse fetal and neonatal ovaries, 14.5-21 days post coitum, to examine the relationship between oocyte development and programmed cell death during meiotic prophase I.

show abstract

Section: Resultssupporting

confidence: 91%

Apoptosis in mouse fetal and neonatal oocytes during meiotic prophase one

2007

View full text Add to dashboard Cite

show abstract

“…It is hypothesised that the residual oogonia occupy postmitotic and premeiotic stages of the cell cycle up to preleptotene, denoted here by an oogonium with condensed chromatin peripheral to the nuclear membrane. The preleptotene stage was described previously as a control point for entry into meiosis and G 1 arrest [147], and also for relapse into mitosis [149,150]. (In S. cerevisiae , reversion to mitosis has been demonstrated during meiotic differentiation, even after premeiotic DNA synthesis [151]).…”

Section: Evidence Advanced For Neo-oogenesismentioning

confidence: 99%

Reinterpretation of evidence advanced for neo-oogenesis in mammals, in terms of a finite oocyte reserve

Notarianni

2011

Journal of Ovarian Research

View full text Add to dashboard Cite

The central tenet of ovarian biology, that the oocyte reserve in adult female mammals is finite, has been challenged over recent years by proponents of neo-oogenesis, who claim that germline stem cells exist in the ovarian surface epithelium or the bone marrow. Currently opinion is divided over these claims, and further scrutiny of the evidence advanced in support of the neo-oogenesis hypothesis is warranted - especially in view of the enormous implications for female fertility and health. This article contributes arguments against the hypothesis, providing alternative explanations for key observations, based on published data. Specifically, DNA synthesis in germ cells in the postnatal mouse ovary is attributed to mitochondrial genome replication, and to DNA repair in oocytes lagging in meiotic progression. Lines purported to consist of germline stem cells are identified as ovarian epithelium or as oogonia, from which cultures have been derived previously. Effects of ovotoxic treatments are found to negate claims for the existence of germline stem cells. And arguments are presented for the misidentification of ovarian somatic cells as de novo oocytes. These clarifications, if correct, undermine the concept that germline stem cells supplement the oocyte quota in the postnatal ovary; and instead comply with the theory of a fixed, unregenerated reserve. It is proposed that acceptance of the neo-oogenesis hypothesis is erroneous, and may effectively impede research in areas of ovarian biology. To illustrate, a novel explanation that is consistent with orthodox theory is provided for the observed restoration of fertility in chemotherapy-treated female mice following bone marrow transplantation, otherwise interpreted by proponents of neo-oogenesis as involving stimulation of endogenous germline stem cells. Instead, it is proposed that the chemotherapeutic regimens induce autoimmunity to ovarian antigens, and that the haematopoietic chimaerism produced by bone marrow transplantation circumvents activation of an autoreactive response, thereby rescuing ovarian function. The suggested mechanism draws from animal models of autoimmune ovarian disease, which implicate dysregulation of T cell regulatory function; and from a surmised role for follicular apoptosis in the provision of ovarian autoantigens, to sustain self-tolerance during homeostasis. This interpretation has direct implications for fertility preservation in women undergoing chemotherapy.

show abstract

“…For EM study, it is possible to use routine techniques (El-Alfy and Leblond, 1989), as also did Wartenberg et al (1998) with remarkable success. However, the osmiumamine procedure is the method of choice, for it yields micrographs free of stained RNA and proteins.…”

Section: Technical Remarksmentioning

confidence: 99%

“…The S phase condensation extended over seven hours, that is, a substantial proportion of the 12.3-hr long cycle of the crypt cells under study (El-Alfy and Leblond, 1988). Finally, chromatin aggregates were recently depicted during the S phase by Wartenberg et al (1998) and Mazzotti et al(1998).…”

mentioning

confidence: 96%

“…Instead, they returned to definitions of prophase and telophase in line with the commonly accepted ones and designated the stages of the cycle by Roman numerals from I to XI, thus assigning seven stages to the interphase and four to mitosis (Table 1, in which stage VI is divided into two substages referred to as VIa or prometaphase and VIb or metaphase). Recently the 11 stages have been identified in an exhaustive LM and EM study of the cycle of rat oogonia, a cell type quite different from duodenal crypt cells (Wartenberg et al, 1998).…”

mentioning

confidence: 99%

See 1 more Smart Citation

The eleven stages of the cell cycle, with emphasis on the changes in chromosomes and nucleoli during interphase and mitosis

Leblond

El‐Alfy

1998

Anat. Rec.

View full text Add to dashboard Cite

Since we had subdivided the cell cycle into 11 stages--four for mitosis and seven for the interphase--and since we had experience in detecting DNA in the electron microscope (EN) by the osmium-amine procedure of Cogliati and Gauthier (Compt. Rend. Acad. Sci., 1973;276:3041-3044), we combined the two approaches for the analysis of DNA-containing structures at all stages of the cell cycle. Thin Epon sections of formaldehyde-fixed mouse duodenum were stained by osmium-amine for electron microscopic examination of the stages in the 12.3-hr long cell cycle of mouse duodenal crypt columnar cells. In addition, semi-thin Lowicryl sections of mouse duodenal crypts and cultured rat kidney cells were stained with the DNA-specific Hoechst 33258 dye and examined in the fluorescence microscope. The DNA detected by osmium-amine is in the form of nucleofilaments, seen at high magnification as long rows of 11 nm-wide rings (consisting of stained DNA encircling unstained histones). At all stages of the cycle as well as in nondividing cells, nucleofilaments are of three types: 'free,' 'attached' to chromatin accumulations, and 'compacted' in all chromatin accumulations, the form of dense spirals within. At stage I of the cycle, besides free and attached nucleofilaments, compacted ones are observed in the three heterochromatin forms (peripheral, nucleolus-associated, clumped). Soon after the S phase begins, chromatin 'aggregates' appear, which are small at stage II, mid-sized at stage III, and large at stage IV. Chromatin 'bulges' also appear at stage III and enlarge at stage IV, while heterochromatins disappear. At stage V, aggregates and bulges accrete into 'chromomeres,' a process responsible for the apparent chromosome condensation observed at prophase. The chromomeres gradually line up in rows and, at stage VIa (prometaphase), approach one another within each row and coalesce to build up the metaphase chromosomes which are fully formed at stage VIb (metaphase). Daughter chromosomes arising at stage VII (anaphase) are eventually packed into a chromosomal mass at each pole of the cell. During stage VIII (telophase), the chromosomal mass is split into large chunks. In the course of the G1 phase, the chunks thin out to give rise to irregular 'bands' at stage IX, the bands are then cleaved into central and peripheral fragments at stage X, and finally the central fragments are replaced by free nucleofilaments and clumps at stage XI, while the peripheral fragments are replaced by peripheral heterochromatin. The "nucleoli" at stages I-III are associated with stained heterochromatin but otherwise appear as unstained lucent areas, except for weakly stained patches composed of histone-free DNA filaments. During stage IV, nucleoli lose patches and associated heterochromatin, while weakly lucent, pale vesicles appear within nucleoli and in the nucleoplasm. By the end of substage VIa, nucleoli generally disappear, while pale vesicles persist around the chromosomes appearing at substage VIb. At stages VIII and IX, the vesicles seem to become ...

show abstract

Germ cell kinetics during early ovarian differentiation: An analysis of the oogonial cell cycle and the subsequent changes in oocyte development during the onset of meiosis in the rat

Cited by 21 publications

References 34 publications

Apoptosis in mouse fetal and neonatal oocytes during meiotic prophase one

Apoptosis in mouse fetal and neonatal oocytes during meiotic prophase one

Reinterpretation of evidence advanced for neo-oogenesis in mammals, in terms of a finite oocyte reserve

The eleven stages of the cell cycle, with emphasis on the changes in chromosomes and nucleoli during interphase and mitosis

Contact Info

Product

Resources

About