scholarly journals CENP-A drives asymmetric cell division and maintains stem identity

2019 ◽  
Author(s):  
Anna A. Dattoli ◽  
Ben L. Carty ◽  
Antje M. Kochendoerfer ◽  
Annie E. Walshe ◽  
Elaine M. Dunleavy
Keyword(s):  
Stem Cell ◽  
Asymmetric Cell Division ◽  
Germline Stem Cells ◽  
Cell Identity ◽  
Over Expression ◽  
Identity Maintenance ◽  
Oocyte Meiosis ◽  
Assembly Factor ◽  
Female Germline ◽  
Centromere Assembly

SUMMARYCentromeres, chromosomal loci essential for genome integrity, are epigenetically defined by CENP-A-containing chromatin. Recent studies suggest that parental CENP-A is asymmetrically distributed upon stem cell asymmetric division. However, a direct link between centromeres and stem cell identity has not been demonstrated. We show that Drosophila female germline stem cells (GSCs) and neuroblasts assemble centromeres between G2-phase and prophase, requiring CYCLIN A. Intriguingly, chromosomes that will be inherited by GSCs incorporate more CENP-A and capture more spindle fibers at pro-metaphase. Furthermore, over-expression of CAL1 (Drosophila CENP-A assembly factor) causes GSC-like tumours, while over-expression of both CENP-A and CAL1 promotes stem cell self-renewal. Finally, once centromeres have been assembled in GSCs, continued CENP-A assembly is not required in differentiating cells outside of the niche and CAL1 becomes dispensable. According to our results CENP-A regulates stem cell identity/maintenance. Moreover, crucial centromere assembly occurs in the niche prior to oocyte meiosis.

scholarly journals Asymmetric assembly of centromeres epigenetically regulates stem cell fate

2020 ◽  
Vol 219 (4) ◽  
Author(s):  
Anna Ada Dattoli ◽  
Ben L. Carty ◽  
Antje M. Kochendoerfer ◽  
Conall Morgan ◽  
Annie E. Walshe ◽  
...  
Keyword(s):  
Stem Cell ◽  
Cell Division ◽  
Cell Fate ◽  
Germline Stem Cells ◽  
Differentiated Cells ◽  
Oocyte Meiosis ◽  
Assembly Factor ◽  
Stem Cell Division ◽  
Female Germline ◽  
Centromere Assembly

Centromeres are epigenetically defined by CENP-A–containing chromatin and are essential for cell division. Previous studies suggest asymmetric inheritance of centromeric proteins upon stem cell division; however, the mechanism and implications of selective chromosome segregation remain unexplored. We show that Drosophila female germline stem cells (GSCs) and neuroblasts assemble centromeres after replication and before segregation. Specifically, CENP-A deposition is promoted by CYCLIN A, while excessive CENP-A deposition is prevented by CYCLIN B, through the HASPIN kinase. Furthermore, chromosomes inherited by GSCs incorporate more CENP-A, making stronger kinetochores that capture more spindle microtubules and bias segregation. Importantly, symmetric incorporation of CENP-A on sister chromatids via HASPIN knockdown or overexpression of CENP-A, either alone or together with its assembly factor CAL1, drives stem cell self-renewal. Finally, continued CENP-A assembly in differentiated cells is nonessential for egg development. Our work shows that centromere assembly epigenetically drives GSC maintenance and occurs before oocyte meiosis.

Centromere assembly and non-random sister chromatid segregation in stem cells

2020 ◽  
Vol 64 (2) ◽  
pp. 223-232 ◽  
Author(s):  
Ben L. Carty ◽  
Elaine M. Dunleavy
Keyword(s):  
Stem Cells ◽  
Cell Division ◽  
Cell Fate ◽  
Sister Chromatid ◽  
Asymmetric Cell Division ◽  
Protein A ◽  
Germline Stem Cells ◽  
Sister Chromatids ◽  
Centromere Protein A ◽  
Oocyte Meiosis

Abstract Asymmetric cell division (ACD) produces daughter cells with separate distinct cell fates and is critical for the development and regulation of multicellular organisms. Epigenetic mechanisms are key players in cell fate determination. Centromeres, epigenetically specified loci defined by the presence of the histone H3-variant, centromere protein A (CENP-A), are essential for chromosome segregation at cell division. ACDs in stem cells and in oocyte meiosis have been proposed to be reliant on centromere integrity for the regulation of the non-random segregation of chromosomes. It has recently been shown that CENP-A is asymmetrically distributed between the centromeres of sister chromatids in male and female Drosophila germline stem cells (GSCs), with more CENP-A on sister chromatids to be segregated to the GSC. This imbalance in centromere strength correlates with the temporal and asymmetric assembly of the mitotic spindle and potentially orientates the cell to allow for biased sister chromatid retention in stem cells. In this essay, we discuss the recent evidence for asymmetric sister centromeres in stem cells. Thereafter, we discuss mechanistic avenues to establish this sister centromere asymmetry and how it ultimately might influence cell fate.

scholarly journals me31B regulates stem cell homeostasis by preventing excess dedifferentiation in the Drosophila male germline

2021 ◽  
Author(s):  
Lindy Jensen ◽  
Zsolt G. Venkei ◽  
George J. Watase ◽  
Bitarka Bisai ◽  
Scott Pletcher ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Critical Role ◽  
Stem Cell Population ◽  
Germline Stem Cells ◽  
Cell Identity ◽  
Stem Cell Maintenance ◽  
Differentiated Cells ◽  
Male Germline ◽  
Elevated Frequency

Tissue-specific stem cells maintain tissue homeostasis by providing a continuous supply of differentiated cells throughout the life of organisms. Differentiated/differentiating cells can revert back to a stem cell identity via dedifferentiation to help maintain the stem cell pool beyond the lifetime of individual stem cells. Although dedifferentiation is important to maintain the stem cell population, it is speculated to underlie tumorigenesis. Therefore, this process must be tightly controlled. Here we show that a translational regulator me31B plays a critical role in preventing excess dedifferentiation in the Drosophila male germline: in the absence of me31B, spermatogonia (SGs) dedifferentiate into germline stem cells (GSCs) at a dramatically elevated frequency. Our results show that the excess dedifferentiation is likely due to misregulation of nos, a key regulator of germ cell identity and GSC maintenance. Taken together, our data reveal negative regulation of dedifferentiation to balance stem cell maintenance with differentiation.

scholarly journals CENP-C regulates centromere assembly, asymmetry and epigenetic age in Drosophila germline stem cells

2020 ◽  
Author(s):  
Ben L Carty ◽  
Anna A Dattoli ◽  
Elaine M Dunleavy
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Fate ◽  
Germ Line ◽  
Asymmetric Distribution ◽  
Germline Stem Cells ◽  
Daughter Cells ◽  
Sister Chromatids ◽  
Asymmetric Divisions ◽  
Centromere Assembly

AbstractGermline stem cells divide asymmetrically to produce one new daughter stem cell and one daughter cell that will subsequently undergo meiosis and differentiate to generate the mature gamete. The silent sister hypothesis proposes that in asymmetric divisions, the selective inheritance of sister chromatids carrying specific epigenetic marks between stem and daughter cells impacts cell fate. To facilitate this selective inheritance, the hypothesis specifically proposes that the centromeric region of each sister chromatid is distinct. In Drosophila germ line stem cells (GSCs), it has recently been shown that the centromeric histone CENP-A (called CID in flies) - the epigenetic determinant of centromere identity - is asymmetrically distributed between sister chromatids. In these cells, CID deposition occurs in G2 phase such that sister chromatids destined to end up in the stem cell harbour more CENP-A, assemble more kinetochore proteins and capture more spindle microtubules. These results suggest a potential mechanism of ‘mitotic drive’ that might bias chromosome segregation. Here we report that the inner kinetochore protein CENP-C, is required for the assembly of CID in G2 phase in GSCs. Moreover, CENP-C is required to maintain a normal asymmetric distribution of CID between stem and daughter cells. In addition, we find that CID is lost from centromeres in aged GSCs and that a reduction in CENP-C accelerates this loss. Finally, we show that CENP-C depletion in GSCs disrupts the balance of stem and daughter cells in the ovary, shifting GSCs toward a self-renewal tendency. Ultimately, we provide evidence that centromere assembly and maintenance via CENP-C is required to sustain asymmetric divisions in female Drosophila GSCs.

scholarly journals ID3019 Female germline stem Cells: A source for application in reproductive and regenerative medicine

2017 ◽  
Vol 4 (S) ◽  
pp. 31
Author(s):  
Thuy Hong Bui
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Ovarian Function ◽  
Primordial Germ Cells ◽  
Postnatal Life ◽  
Proliferative Potential ◽  
Germline Stem Cells ◽  
Mammalian Female ◽  
Female Germline

Studies suggest a renewable source of eggs and stir more controversy, especially about the origin of female germline stem cells (FGSCs). It should be elucidated whether or not neo-oogenesis continues in the ovaries of mammalian female during postnatal life. Therefore, the establishment of FGSCs is very important for many applications. Here, using adult pig ovary, we isolate, identify, characterize FGSCs to elucidate their origin, then examined the proliferation, growth and differentiation of them. These cells were heterogeneous, depending on both of c-kit expression and cell size, and also express stem cell and germ cell markers. Importantly, we show clearly that the cells with the characteristics of early primordial germ cells are present in the adult pig ovary. Once FGSCs were established, they could be expanded in vitro for months without loss of the identifying markers and proliferative potential. Under appropriate conditions, the FGSCs differentiated into primordial oocyte-like cells and grow close to full-sized oocytes. These may assist in therapeutic strategies in human with their potential to make new oocytes and support ovarian function and fertility. Our results support the theory that the ovary contains a small number of undifferentiated cells with stem cell characteristics. These might remain in the postnatal and adult ovary and under certain conditions could resume mitosis, enter meiosis and give rise to oocytes. Given the existence of these FGSCs in mammalian ovaries and the depletion in ovarian reserve during female reproductive aging, one can hypothesize that such “neo-oogenesis” was present in ancestral forms, is still present in insects, some fish and mollusks, but has been lost in land vertebrates through evolution. FGSCs cannot proliferate in the ovary normally because of inhibitory factors, but under appropriate conditions, they can undergo proliferation and differentiation, and provide a potential mechanism for the self-renewal of germline stem cells.

scholarly journals Effects of shikonin on the development of ovarian follicles and female germline stem cells

2021 ◽  
Vol 49 (7) ◽  
pp. 030006052110294
Author(s):  
Shu-Xin Ma ◽  
Li-Bo Tang ◽  
Zhi-Hang Chen ◽  
Min-Li Wei ◽  
Zi-Juan Tang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Ovarian Follicles ◽  
Germline Stem Cell ◽  
Stem Cell Markers ◽  
Germline Stem Cells ◽  
Primordial Follicles ◽  
Cell Markers ◽  
Female Germline ◽  
Ovarian Index

Objective To investigate the effects and potential mechanism of action of shikonin (SHK) on the development of ovarian follicles and female germline stem cells (FGSCs). Methods Female Kunming adult mice were administered SHK (0, 20 and 50 mg/kg) by oral gavage. Cultures of FGSCs were treated with SHK 32 μmol/l for 24 h. The ovarian index in mouse ovaries was calculated. Numbers of primordial, primary and atretic follicles were counted. Germline stem cell markers and apoptosis were examined. Levels of glutathione (GSH), superoxide dismutase (SOD) and reactive oxygen species (ROS) were measured. Results Both doses of SHK significantly decreased the ovarian index, the numbers of primordial follicles, primary follicles and antral follicles in mice. SHK significantly increased the numbers of atretic follicles and atretic corpora lutea. SHK promoted apoptosis in vivo and in vitro. SHK significantly decreased the levels of the germline stem cell markers. SHK significantly lowered GSH levels and the activity of SOD in the peripheral blood from mice, whereas SHK significantly elevated cellular ROS content in FGSCs. Conclusions These current results suggested that follicular development and FGSCs were suppressed by SHK through the induction of apoptosis and oxidative stress might be involved in this pathological process.

scholarly journals CENP-C functions in centromere assembly, the maintenance of CENP-A asymmetry and epigenetic age in Drosophila germline stem cells

PLoS Genetics ◽  
2021 ◽  
Vol 17 (5) ◽  
pp. e1009247
Author(s):  
Ben L. Carty ◽  
Anna A. Dattoli ◽  
Elaine M. Dunleavy
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Fate ◽  
Germ Line ◽  
Asymmetric Distribution ◽  
Germline Stem Cells ◽  
Daughter Cells ◽  
Sister Chromatids ◽  
Asymmetric Divisions ◽  
Centromere Assembly

Germline stem cells divide asymmetrically to produce one new daughter stem cell and one daughter cell that will subsequently undergo meiosis and differentiate to generate the mature gamete. The silent sister hypothesis proposes that in asymmetric divisions, the selective inheritance of sister chromatids carrying specific epigenetic marks between stem and daughter cells impacts cell fate. To facilitate this selective inheritance, the hypothesis specifically proposes that the centromeric region of each sister chromatid is distinct. In Drosophila germ line stem cells (GSCs), it has recently been shown that the centromeric histone CENP-A (called CID in flies)—the epigenetic determinant of centromere identity—is asymmetrically distributed between sister chromatids. In these cells, CID deposition occurs in G2 phase such that sister chromatids destined to end up in the stem cell harbour more CENP-A, assemble more kinetochore proteins and capture more spindle microtubules. These results suggest a potential mechanism of ‘mitotic drive’ that might bias chromosome segregation. Here we report that the inner kinetochore protein CENP-C, is required for the assembly of CID in G2 phase in GSCs. Moreover, CENP-C is required to maintain a normal asymmetric distribution of CID between stem and daughter cells. In addition, we find that CID is lost from centromeres in aged GSCs and that a reduction in CENP-C accelerates this loss. Finally, we show that CENP-C depletion in GSCs disrupts the balance of stem and daughter cells in the ovary, shifting GSCs toward a self-renewal tendency. Ultimately, we provide evidence that centromere assembly and maintenance via CENP-C is required to sustain asymmetric divisions in female Drosophila GSCs.

scholarly journals The asymmetric segregation of damaged proteins is stem cell–type dependent

2013 ◽  
Vol 201 (4) ◽  
pp. 523-530 ◽  
Author(s):  
Mary Rose Bufalino ◽  
Brian DeVeale ◽  
Derek van der Kooy
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Adult Stem Cells ◽  
Intestinal Stem Cell ◽  
Germline Stem Cells ◽  
Cell Type ◽  
Chronological Life Span ◽  
A Cell ◽  
Female Germline

Asymmetric segregation of damaged proteins (DPs) during mitosis has been linked in yeast and bacteria to the protection of one cell from aging. Recent evidence suggests that stem cells may use a similar mechanism; however, to date there is no in vivo evidence demonstrating this effect in healthy adult stem cells. We report that stem cells in larval (neuroblast) and adult (female germline and intestinal stem cell) Drosophila melanogaster asymmetrically segregate DPs, such as proteins with the difficult-to-degrade and age-associated 2,4-hydroxynonenal (HNE) modification. Surprisingly, of the cells analyzed only the intestinal stem cell protects itself by segregating HNE to differentiating progeny, whereas the neuroblast and germline stem cells retain HNE during division. This led us to suggest that chronological life span, and not cell type, determines the amount of DPs a cell receives during division. Furthermore, we reveal a role for both niche-dependent and -independent mechanisms of asymmetric DP division.

scholarly journals ID: 1063 Isolation and characterization of female germline stem cell derived from porcine ovary

2017 ◽  
Vol 4 (S) ◽  
pp. 145
Author(s):  
Nguyen Huy Hoang ◽  
Nguyen Thi Bao Tran ◽  
Nguyen Van Thuan ◽  
Bui Hong Thuy
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
In Vitro Culture ◽  
Germline Stem Cell ◽  
Stem Cell Markers ◽  
Significant Finding ◽  
Germline Stem Cells ◽  
Isolation And Characterization ◽  
Female Germline

One of the most significant finding in stem cell area in the early 21st century is the founding of female germline stem cells (FGSCs). Establishment of FGSCs allowed new possibilities for the use of them in biotechnology and medicine. Hence, the purpose of this study was to establish, characterize the porcine female germline stem cells (pFGSCs) from porcine ovary. The result revealed the success in establishing pFGSCs from ovarian tissue. Most of the pFGSCs were round shape after in vitro culture, forming groups of cells that cluster around the ovarian cells colonies. Immunofluorescent analysis of pFGSCs showed that these cells expressed germ cell and stem cell markers such as: Vasa, Stella, c-kit and Oct4. After several weeks in in vitro culture, pFGSCs increased in number without the loss of proliferative potential. Our results suggested that pFGSCs isolated from adult mammalian ovary, under appropriate conditions, could undergo proliferation.

scholarly journals me31B regulates stem cell homeostasis by preventing excess dedifferentiation in the Drosophila male germline

2021 ◽  
Author(s):  
Lindy Jensen ◽  
Zsolt G. Venkei ◽  
George J. Watase ◽  
Bitarka Bisai ◽  
Scott Pletcher ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Critical Role ◽  
Stem Cell Population ◽  
Germline Stem Cells ◽  
Cell Identity ◽  
Stem Cell Maintenance ◽  
Differentiated Cells ◽  
Male Germline ◽  
Elevated Frequency

AbstractTissue-specific stem cells maintain tissue homeostasis by providing a continuous supply of differentiated cells throughout the life of organisms. Differentiated/differentiating cells can revert back to a stem cell identity via dedifferentiation to help maintain the stem cell pool beyond the lifetime of individual stem cells. Although dedifferentiation is important to maintain the stem cell population, it is speculated to underlie tumorigenesis. Therefore, this process must be tightly controlled. Here we show that a translational regulator me31B plays a critical role in preventing excess dedifferentiation in the Drosophila male germline: in the absence of me31B, spermatogonia (SGs) dedifferentiate into germline stem cells (GSCs) at a dramatically elevated frequency. Our results show that the excess dedifferentiation is likely due to misregulation of nos, a key regulator of germ cell identity and GSC maintenance. Taken together, our data reveal negative regulation of dedifferentiation to balance stem cell maintenance with differentiation.

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