Kinetics of gametogenesis

Stra8 (stimulated by retinoic acid 8) encodes a protein crucial for mammalian germ cells entering into premeiotic stages. Here, to elucidate the still unknown STRA8 molecular functions, we studied the cellular localization of the protein in several cell types, including premeiotic mouse germ cells and stem cell lines. We reported distinct STRA8 localization in germ and stem cell types and a heterogeneous protein distribution in the cytoplasm and nucleus of such cells suggesting that the protein can shuttle between these two compartments. Moreover, we identified specific protein motifs determining its nuclear import/export. Furthermore, we demonstrated that in transfected cell lines the nuclear import of STRA8 is an active process depending on an N-terminal basic nuclear localization signal. Moreover, its nuclear export is mainly mediated by the Exportin1 (XPO1) recognition of a nuclear export signal. Significantly, we also demonstrated that STRA8 associates with DNA and possesses transcriptional activity. These observations strongly suggest that STRA8 can exert important functions in the nucleus rather than in the cytoplasm as believed previously, likely depending on the cell type and regulated by its nuclear-cytoplasmic shuttling.

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“…mitotic block in G 0 /G 1 (2). Although in about 55% of the STRA8-positive PGCs, STRA8 was evenly localized in the cytoplasm and nucleus (Fig.…”

Section: Resultsmentioning

confidence: 95%

“…They are the only cells able to divide meiotically and to halve their genetic material generating haploid cells. In the mouse ovary, oocytes begin meiosis during fetal development around 13.5 days post-coitum (dpc) 2 (1), whereas in the testis the onset of meiosis is delayed until after birth (2).…”

mentioning

confidence: 99%

STRA8 Shuttles between Nucleus and Cytoplasm and Displays Transcriptional Activity

Tedesco

Sala

Barbagallo

et al. 2009

Journal of Biological Chemistry

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“…During colonization, PGCs form nests of closely associated germ cells organized into long ovigerous cords, bordered by a basal lamina which provides a physical separation between the germ cells and the surrounding pre-granulosa and mesenchymal stroma cells (Konishi et al, 1986; Heeren et al, 2015). In mice, formation of the nests begins at e12.5 and continues until meiotic arrest is complete at e16.5 (Hilscher et al, 1974; Menke et al, 2003; Bullejos and Koopman, 2004) and in humans at approximately nine weeks of development (Baker and Franchi, 1967; Motta and Makabe, 1986). Shortly after birth, mouse germ cell nests break down during a process accompanied by significant loss of oogonia as a result of apoptosis (Pepling and Spradling, 2001).…”

Section: Ovarian Germ Cells: Primordial Germ Cells (Pgcs) and Oogomentioning

confidence: 99%

Ovarian regeneration: The potential for stem cell contribution in the postnatal ovary to sustained endocrine function

Truman

Tilly

Woods

2017

Molecular and Cellular Endocrinology

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The endocrine function of the ovary is dependent upon the ovarian follicle, which on a cellular basis consists of an oocyte surrounded by adjacent somatic cells responsible for generating sex steroid hormones and maintenance of hormonal stasis with the hypothalamic-pituitary axis. As females age, both fertility and the endocrine function of the ovary decline due to waning follicle numbers as well as aging-related cellular dysfunction. Although there is currently no cure for ovarian failure and endocrine disruption, recent advances in ovarian biology centered on ovarian stem cell and progenitor cell populations have brought the prospects of cell- or tissue-based therapeutic strategies closer to fruition. Herein, we review the relative contributions of ovarian stem cells to ovarian function during the reproductive lifespan, and postulate steps toward the development of ovarian stem cell-based approaches to advance fertility treatments, and also importantly to provide a physiological long-term means of endocrine support.

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“…They migrate into gonads with the help of chemotaxis factors, such as c-kit/Kit and kit ligand/Kitl,15,26,110,111 until 10.5 dpc and rapidly proliferate from approximately 40 to 25,000 in number between 7.5 and 13.5 dpc 95. During this period, PGCs become progressively different from their ancestors; over time, they exhibit the repression of genes characteristic of their neighboring somatic cells,83 reprogramming including the erasure of genomic imprinting,41,61,88,89 and the acquisition of sexuality 1,36,57,84. Consequently, they are ready for oogenesis or spermatogenesis.…”

Section: Introductionmentioning

confidence: 99%

Differentiation of Mouse Primordial Germ Cells into Functional Oocytes In Vitro

2017

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Various complex molecular events in oogenesis cannot be observed in vivo. As a bioengineering technique for female reproductive tissues, in vitro culture systems for female germ cells have been used to analyze oogenesis and preserve germ cells for over 20 years. Recently, we have established a new methodological approach for the culture of primordial germ cells (PGCs) and successfully obtained offspring. Our PGC culture system will be useful to clarify unresolved mechanisms of fertility and sterility from the beginning of mammalian oogenesis, before meiosis. This review summarizes the history of culture methods for mammalian germ cells, our current in vitro system, and future prospects for the culture of germ cells.

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Kinetics of gametogenesis

Cited by 163 publications

References 30 publications

STRA8 Shuttles between Nucleus and Cytoplasm and Displays Transcriptional Activity

STRA8 Shuttles between Nucleus and Cytoplasm and Displays Transcriptional Activity

Ovarian regeneration: The potential for stem cell contribution in the postnatal ovary to sustained endocrine function

Differentiation of Mouse Primordial Germ Cells into Functional Oocytes In Vitro

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