Germ cell development in female pouch young of the tammar wallaby (Macropus eugenii)

Alcorn, G. T.; Robinson, E. S.

doi:10.1530/jrf.0.0670319

Cited by 36 publications

(26 citation statements)

References 10 publications

(14 reference statements)

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“…Gonadal initiation, in terms of the origin and migration of primordial germ cells, follows a pattern similar to that seen in eutherians (Tyndale-Biscoe and Renfree, 1987). Primordial germ cells appear along the dorsal mesentery surrounding the hindgut in mid-late gestation and then migrate laterally and emerge in the gonadal ridges dorsal to the mesonephros (Alcorn and Robinson, 1983: Macropus eugenii; Ullman, 1993: T . vulpecula).…”

Section: Ommentioning

confidence: 67%

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A morphometric study of early ovarian development in pouch young of the brushtail possum (Trichosurus vulpecula)

et al. 1996

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Section: Ommentioning

confidence: 67%

“…Despite this well-documented timetable of sexual differentiation in marsupials, there is a paucity of temporal information on changes in cytology, timing, or the growth of germ cells. The only study that specifically addressed these factors was that of Alcorn and Robinson (1983), which was restricted to M .…”

Section: Ommentioning

confidence: 99%

A morphometric study of early ovarian development in pouch young of the brushtail possum (Trichosurus vulpecula)

et al. 1996

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“…In the tammar wallaby, most germ cell migration is completed 1 day before birth [Alcorn and Robinson, 1983;Jiang et al, 1997;Ullmann et al, 1997]. Unlike the bandicoots Isoodon macrourus [Ullmann, 1989], M. domestica [Fadem et al, 1992;Maitland and Ullmann, 1993] and Trichosurus vulpecula [Ullmann, 1993;Frankenberg et al, 1996] in S. macroura the migration of PGC to the indifferent gonad is completed by the day of birth.…”

Section: Discussionmentioning

confidence: 99%

Oogenesis in the Marsupial Stripe-Faced Dunnart, <i>Sminthopsis macroura</i>

Kress

Merry

Selwood

2001

Cells Tissues Organs

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The timetable of oogenesis in Sminthopsis macroura is accelerated like in other marsupials showing relatively early maturation of the female. On the day of parturition (day 0) migration of primordial germ cells to the indifferent gonads has been completed. Follicular growth seems not to correspond to the biphasic pattern, in which oocyte and follicle grow synchronously until antral stages when only the follicle increases in size, but shows a continuous growth of the oocyte and the follicle up to the time of ovulation. During primordial and early primary follicle stage a paranuclear complex is present in the oocyte, consisting mainly of smooth tubules of endoplasmic reticulum. Cortical granules appear early in oocytes in secondary follicles. The conspicuous inclusions in the antral follicle are the clusters of electron-lucent vesicles in the oocyte. These inclusions grow from multivesicular bodies (MVB), which are formed from Golgi and endoplasmic reticulum vesicles. Further increase in the size of MVB involves the incorporation of endocytic vesicles and the coalescence of larger vesicles. The polarized nature of the oocyte at ovulation is due in part to the to accumulation of these vesicles in the cytoplasm opposite the eccentrically placed nuclear material.

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“…As development proceeds in the tammar ovary, germ cells aggregate into clusters and divide mitotically within the cortex up to day 25 pp, when the germ cells begin to enter meiosis (Alcorn & Robinson 1983). There was a notable increase in both receptor proteins during this phase, but this was more pronounced for tESR2 than tESR1.…”

Section: Ers In the Developing And Adult Ovarymentioning

confidence: 99%

Ontogeny of the oestrogen receptors ESR1 and ESR2 during gonadal development in the tammar wallaby, Macropus eugenii

Calatayud¹,

Pask²,

Shaw³

et al. 2010

Reproduction

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Oestrogen has wide ranging effects in development mediated mainly via the two oestrogen receptors, a (ESR1, also known as ERa) and b (ESR2, also known as ERb). Oestrogen is the key factor that directs the indifferent gonad to become an ovary in many non-mammalian vertebrates. Oestrogen is not required for early ovarian differentiation in mammals but can disrupt normal testicular development in eutherians. Surprisingly, exogenous oestrogen can cause sex reversal of an XY gonad in two marsupials, the North American opossum and the tammar wallaby. To understand the mechanism by which oestrogen induces sex reversal, we characterised the genes for ESR1 and ESR2 and examined their expression during gonadal differentiation in the tammar wallaby, Macropus eugenii. Both receptors were expressed in the somatic cells and germ cells of the indifferent gonad in both XX and XY foetuses throughout all stages of development, and persisted in these cells into adulthood. ERs were also present in many other tissues including kidney, pituitary and mammary gland. ER mRNA was not significantly altered by exogenous oestrogen in cultured XY gonads but the receptors translocated to the nucleus in its presence. These findings confirm that there is conserved expression of the ERs in the indifferent gonad despite the lack of available ligand during early gonadal development. The receptors can respond to exogenous estrogen at this early stage and are capable of transducing signals in the early mammalian gonad. However, the selective forces that maintained conserved ER expression in this tissue remain unknown.

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Germ cell development in female pouch young of the tammar wallaby (Macropus eugenii)

Abstract: Summary. The

Cited by 36 publications

References 10 publications

A morphometric study of early ovarian development in pouch young of the brushtail possum (Trichosurus vulpecula)

A morphometric study of early ovarian development in pouch young of the brushtail possum (Trichosurus vulpecula)

Oogenesis in the Marsupial Stripe-Faced Dunnart, <i>Sminthopsis macroura</i>

Ontogeny of the oestrogen receptors ESR1 and ESR2 during gonadal development in the tammar wallaby, Macropus eugenii

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