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Bolkent S. Cellular and molecular mechanisms of asymmetric stem cell division in tissue homeostasis. Genes Cells 2024. [PMID: 39379096 DOI: 10.1111/gtc.13172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 09/09/2024] [Accepted: 09/25/2024] [Indexed: 10/10/2024]
Abstract
The asymmetric cell division determines cell diversity and distinct sibling cell fates by mechanisms linked to mitosis. Many adult stem cells divide asymmetrically to balance self-renewal and differentiation. The process of asymmetric cell division involves an axis of polarity and, second, the localization of cell fate determinants at the cell poles. Asymmetric division of stem cells is achieved by intrinsic and extrinsic fate determinants such as signaling molecules, epigenetics factors, molecules regulating gene expression, and polarized organelles. At least some stem cells perform asymmetric and symmetric cell divisions during development. Asymmetric division ensures that the number of stem cells remains constant throughout life. The asymmetric division of stem cells plays an important role in biological events such as embryogenesis, tissue regeneration and carcinogenesis. This review summarizes recent advances in the regulation of asymmetric stem cell division in model organisms.
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Affiliation(s)
- Sema Bolkent
- Cerrahpaşa Faculty of Medicine, Department of Medical Biology, Istanbul University-Cerrahpaşa, Cerrahpaşa, Istanbul, Turkey
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2
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Watase GJ, Yamashita YM. RNA polymerase II-mediated rDNA transcription mediates rDNA copy number expansion in Drosophila. PLoS Genet 2024; 20:e1011136. [PMID: 38758955 PMCID: PMC11139327 DOI: 10.1371/journal.pgen.1011136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 05/30/2024] [Accepted: 05/08/2024] [Indexed: 05/19/2024] Open
Abstract
Ribosomal DNA (rDNA), which encodes ribosomal RNA, is an essential but unstable genomic element due to its tandemly repeated nature. rDNA's repetitive nature causes spontaneous intrachromatid recombination, leading to copy number (CN) reduction, which must be counteracted by a mechanism that recovers CN to sustain cells' viability. Akin to telomere maintenance, rDNA maintenance is particularly important in cell types that proliferate for an extended time period, most notably in the germline that passes the genome through generations. In Drosophila, the process of rDNA CN recovery, known as 'rDNA magnification', has been studied extensively. rDNA magnification is mediated by unequal sister chromatid exchange (USCE), which generates a sister chromatid that gains the rDNA CN by stealing copies from its sister. However, much remains elusive regarding how germ cells sense rDNA CN to decide when to initiate magnification, and how germ cells balance between the need to generate DNA double-strand breaks (DSBs) to trigger USCE vs. avoiding harmful DSBs. Recently, we identified an rDNA-binding Zinc-finger protein Indra as a factor required for rDNA magnification, however, the underlying mechanism of action remains unknown. Here we show that Indra is a negative regulator of rDNA magnification, balancing the need of rDNA magnification and repression of dangerous DSBs. Mechanistically, we show that Indra is a repressor of RNA polymerase II (Pol II)-dependent transcription of rDNA: Under low rDNA CN conditions, Indra protein amount is downregulated, leading to Pol II-mediated transcription of rDNA. This results in the expression of rDNA-specific retrotransposon, R2, which we have shown to facilitate rDNA magnification via generation of DBSs at rDNA. We propose that differential use of Pol I and Pol II plays a critical role in regulating rDNA CN expansion only when it is necessary.
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Affiliation(s)
- George J. Watase
- Department of Germline Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Chuo-ku, Kumamoto-shi, Kumamoto, JAPAN
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Yukiko M. Yamashita
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, United States of America
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
- Howard Hughes Medical Institute, Cambridge, Massachusetts, United States of America
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3
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Snedeker J, Davis BEM, Ranjan R, Wooten M, Blundon J, Chen X. Reduced Levels of Lagging Strand Polymerases Shape Stem Cell Chromatin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.26.591383. [PMID: 38746451 PMCID: PMC11092439 DOI: 10.1101/2024.04.26.591383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Stem cells display asymmetric histone inheritance while non-stem progenitor cells exhibit symmetric patterns in the Drosophila male germline lineage. Here, we report that components involved in lagging strand synthesis, such as DNA polymerase α and δ (Polα and Polδ), have significantly reduced levels in stem cells compared to progenitor cells. Compromising Polα genetically induces the replication-coupled histone incorporation pattern in progenitor cells to be indistinguishable from that in stem cells, which can be recapitulated using a Polα inhibitor in a concentration-dependent manner. Furthermore, stem cell-derived chromatin fibers display a higher degree of old histone recycling by the leading strand compared to progenitor cell-derived chromatin fibers. However, upon reducing Polα levels in progenitor cells, the chromatin fibers now display asymmetric old histone recycling just like GSC-derived fibers. The old versus new histone asymmetry is comparable between stem cells and progenitor cells at both S-phase and M-phase. Together, these results indicate that developmentally programmed expression of key DNA replication components is important to shape stem cell chromatin. Furthermore, manipulating one crucial DNA replication component can induce replication-coupled histone dynamics in non-stem cells in a manner similar to that in stem cells.
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Affiliation(s)
- Jonathan Snedeker
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Brendon E. M. Davis
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Rajesh Ranjan
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
- Howard Hughes Medical Institute, Department of Biology, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Baltimore, MD 21218, USA
| | - Matthew Wooten
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
- Current address: Fred Hutchinson Cancer Research Center, Seattle, WA 98109-1024, USA
| | - Joshua Blundon
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Xin Chen
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
- Howard Hughes Medical Institute, Department of Biology, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Baltimore, MD 21218, USA
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4
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Yamashita YM. Asymmetric Stem Cell Division and Germline Immortality. Annu Rev Genet 2023; 57:181-199. [PMID: 37552892 DOI: 10.1146/annurev-genet-022123-040039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
Germ cells are the only cell type that is capable of transmitting genetic information to the next generation, which has enabled the continuation of multicellular life for the last 1.5 billion years. Surprisingly little is known about the mechanisms supporting the germline's remarkable ability to continue in this eternal cycle, termed germline immortality. Even unicellular organisms age at a cellular level, demonstrating that cellular aging is inevitable. Extensive studies in yeast have established the framework of how asymmetric cell division and gametogenesis may contribute to the resetting of cellular age. This review examines the mechanisms of germline immortality-how germline cells reset the aging of cells-drawing a parallel between yeast and multicellular organisms.
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Affiliation(s)
- Yukiko M Yamashita
- Whitehead Institute for Biomedical Research, Howard Hughes Medical Institute, and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA;
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5
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Hétié P, de Cuevas M, Matunis EL. The adult Drosophila testis lacks a mechanism to replenish missing niche cells. Development 2023; 150:dev201148. [PMID: 36503989 PMCID: PMC10110489 DOI: 10.1242/dev.201148] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 11/29/2022] [Indexed: 12/14/2022]
Abstract
The adult Drosophila testis contains a well-defined niche created by a cluster of hub cells, which secrete signals that maintain adjacent germline stem cells and somatic cyst stem cells (CySCs). Hub cells are normally quiescent in adult flies but can exit quiescence, delaminate from the hub and convert into CySCs after ablation of all CySCs. The opposite event, CySC conversion into hub cells, was proposed to occur under physiological conditions, but the frequency of this event is debated. Here, to probe further the question of whether or not hub cells can be regenerated, we developed methods to genetically ablate some or all hub cells. Surprisingly, when flies were allowed to recover from ablation, the missing hub cells were not replaced. Hub cells did not exit quiescence after partial ablation of hub cells, and labeled cells from outside the hub did not enter the hub during or after ablation. Despite its ability to exit quiescence in response to CySC ablation, we conclude that the hub in the adult Drosophila testis does not have a mechanism to replenish missing hub cells.
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Affiliation(s)
- Phylis Hétié
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA
| | - Margaret de Cuevas
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA
| | - Erika L. Matunis
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA
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6
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Ranjan R, Snedeker J, Wooten M, Chu C, Bracero S, Mouton T, Chen X. Differential condensation of sister chromatids acts with Cdc6 to ensure asynchronous S-phase entry in Drosophila male germline stem cell lineage. Dev Cell 2022; 57:1102-1118.e7. [PMID: 35483360 PMCID: PMC9134767 DOI: 10.1016/j.devcel.2022.04.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 01/16/2022] [Accepted: 04/05/2022] [Indexed: 01/06/2023]
Abstract
During Drosophila melanogaster male germline stem cell (GSC) asymmetric division, preexisting old versus newly synthesized histones H3 and H4 are asymmetrically inherited. However, the biological outcomes of this phenomenon have remained unclear. Here, we tracked old and new histones throughout the GSC cell cycle through the use of high spatial and temporal resolution microscopy. We found unique features that differ between old and new histone-enriched sister chromatids, including differences in nucleosome density, chromosomal condensation, and H3 Ser10 phosphorylation. These distinct chromosomal features lead to their differential association with Cdc6, a pre-replication complex component, and subsequent asynchronous DNA replication initiation in the resulting daughter cells. Disruption of asymmetric histone inheritance abolishes differential Cdc6 association and asynchronous S-phase entry, demonstrating that histone asymmetry acts upstream of these critical cell-cycle progression events. Furthermore, disruption of these GSC-specific chromatin features leads to GSC defects, indicating a connection between histone inheritance, cell-cycle progression, and cell fate determination.
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Affiliation(s)
- Rajesh Ranjan
- Howard Hughes Medical Institute, Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA; Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA.
| | - Jonathan Snedeker
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Matthew Wooten
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Carolina Chu
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Sabrina Bracero
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Taylar Mouton
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Xin Chen
- Howard Hughes Medical Institute, Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA; Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA.
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7
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Centromere assembly and non-random sister chromatid segregation in stem cells. Essays Biochem 2021; 64:223-232. [PMID: 32406510 DOI: 10.1042/ebc20190066] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 04/21/2020] [Accepted: 04/30/2020] [Indexed: 01/17/2023]
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.
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8
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Abstract
The loss of genetic fidelity in tissue stem cells is considered a significant cause of human aging and carcinogenesis. Many cellular mechanisms are well accepted for limiting mutations caused by replication errors and DNA damage. However, one mechanism, non-random sister chromatid segregation, remains controversial. This atypical pattern of chromosome segregation is restricted to asymmetrically self-renewing cells. Though first confirmed in murine cells, non-random segregation was originally proposed by Cairns as an important genetic fidelity mechanism in human tissues. We investigated human hepatic stem cells expanded by suppression of asymmetric cell kinetics (SACK) for evidence of non-random sister chromatid segregation. Cell kinetics and time-lapse microscopy analyses established that an ex vivo expanded human hepatic stem cell strain possessed SACK agent-suppressible asymmetric cell kinetics. Complementary DNA strand-labeling experiments revealed that cells in hepatic stem cell cultures segregated sister chromatids non-randomly. The number of cells cosegregating sister chromatids with the oldest “immortal DNA strands” was greater under conditions that increased asymmetric self-renewal kinetics. Detection of this mechanism in a human tissue stem cell strain increases support for Cairns’ proposal that non-random sister chromatid segregation operates in human tissue stem cells to limit carcinogenesis.
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9
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Ma B, Trieu TJ, Cheng J, Zhou S, Tang Q, Xie J, Liu JL, Zhao K, Habib SJ, Chen X. Differential Histone Distribution Patterns in Induced Asymmetrically Dividing Mouse Embryonic Stem Cells. Cell Rep 2020; 32:108003. [PMID: 32783931 PMCID: PMC7962874 DOI: 10.1016/j.celrep.2020.108003] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 11/03/2019] [Accepted: 07/15/2020] [Indexed: 12/14/2022] Open
Abstract
Wnt3a-coated beads can induce asymmetric divisions of mouse embryonic stem cells (mESCs), resulting in one self-renewed mESC and one differentiating epiblast stem cell. This provides an opportunity for studying histone inheritance pattern at a single-cell resolution in cell culture. Here, we report that mESCs with Wnt3a-bead induction display nonoverlapping preexisting (old) versus newly synthesized (new) histone H3 patterns, but mESCs without Wnt3a beads have largely overlapping patterns. Furthermore, H4K20me2/3, an old histone-enriched modification, displays a higher instance of asymmetric distribution on chromatin fibers from Wnt3a-induced mESCs than those from non-induced mESCs. These locally distinct distributions between old and new histones have both cellular specificity in Wnt3a-induced mESCs and molecular specificity for histones H3 and H4. Given that post-translational modifications at H3 and H4 carry the major histone modifications, our findings provide a mammalian cell culture system to study histone inheritance for maintaining stem cell fate and for resetting it during differentiation.
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Affiliation(s)
- Binbin Ma
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA; Research Center for Regenerative Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai 200120, China; Key Laboratory for the Genetics of Developmental & Neuropsychiatric Disorders (Ministry of Education), Bio-X Institutes, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Tung-Jui Trieu
- Centre for Stem Cells and Regenerative Medicine, King's College London, London SE1 9RT, UK
| | - Ji Cheng
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA; Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218, USA
| | - Shuang Zhou
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Qingsong Tang
- Systems Biology Center, Division of Intramural Research, NHLBI, NIH, Bethesda, MD, USA
| | - Jing Xie
- Research Center for Regenerative Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai 200120, China
| | - Ji-Long Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Keji Zhao
- Systems Biology Center, Division of Intramural Research, NHLBI, NIH, Bethesda, MD, USA
| | - Shukry J Habib
- Centre for Stem Cells and Regenerative Medicine, King's College London, London SE1 9RT, UK
| | - Xin Chen
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA.
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10
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Wooten M, Ranjan R, Chen X. Asymmetric Histone Inheritance in Asymmetrically Dividing Stem Cells. Trends Genet 2020; 36:30-43. [PMID: 31753528 PMCID: PMC6925335 DOI: 10.1016/j.tig.2019.10.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/21/2019] [Accepted: 10/15/2019] [Indexed: 12/26/2022]
Abstract
Epigenetic mechanisms play essential roles in determining distinct cell fates during the development of multicellular organisms. Histone proteins represent crucial epigenetic components that help specify cell identities. Previous work has demonstrated that during the asymmetric cell division of Drosophila male germline stem cells (GSCs), histones H3 and H4 are asymmetrically inherited, such that pre-existing (old) histones are segregated towards the self-renewing GSC whereas newly synthesized (new) histones are enriched towards the differentiating daughter cell. In order to further understand the molecular mechanisms underlying this striking phenomenon, two key questions must be answered: when and how old and new histones are differentially incorporated by sister chromatids, and how epigenetically distinct sister chromatids are specifically recognized and segregated. Here, we discuss recent advances in our understanding of the molecular mechanisms and cellular bases underlying these fundamental and important biological processes responsible for generating two distinct cells through one cell division.
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Affiliation(s)
- Matthew Wooten
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Rajesh Ranjan
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Xin Chen
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA.
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11
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Asymmetric Centromeres Differentially Coordinate with Mitotic Machinery to Ensure Biased Sister Chromatid Segregation in Germline Stem Cells. Cell Stem Cell 2019; 25:666-681.e5. [PMID: 31564548 DOI: 10.1016/j.stem.2019.08.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 06/25/2019] [Accepted: 08/19/2019] [Indexed: 12/29/2022]
Abstract
Many stem cells utilize asymmetric cell division (ACD) to produce a self-renewed stem cell and a differentiating daughter cell. How non-genic information could be inherited differentially to establish distinct cell fates is not well understood. Here, we report a series of spatiotemporally regulated asymmetric components, which ensure biased sister chromatid attachment and segregation during ACD of Drosophila male germline stem cells (GSCs). First, sister centromeres are differentially enriched with proteins involved in centromere specification and kinetochore function. Second, temporally asymmetric microtubule activities and polarized nuclear envelope breakdown allow for the preferential recognition and attachment of microtubules to asymmetric sister kinetochores and sister centromeres. Abolishment of either the asymmetric sister centromeres or the asymmetric microtubule activities results in randomized sister chromatid segregation. Together, these results provide the cellular basis for partitioning epigenetically distinct sister chromatids during stem cell ACDs, which opens new directions to study these mechanisms in other biological contexts.
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12
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Abstract
Gametogenesis represents the most dramatic cellular differentiation pathways in both female and male flies. At the genome level, meiosis ensures that diploid germ cells become haploid gametes. At the epigenome level, extensive changes are required to turn on and shut off gene expression in a precise spatiotemporally controlled manner. Research applying conventional molecular genetics and cell biology, in combination with rapidly advancing genomic tools have helped us to investigate (1) how germ cells maintain lineage specificity throughout their adult reproductive lifetime; (2) what molecular mechanisms ensure proper oogenesis and spermatogenesis, as well as protect genome integrity of the germline; (3) how signaling pathways contribute to germline-soma communication; and (4) if such communication is important. In this chapter, we highlight recent discoveries that have improved our understanding of these questions. On the other hand, restarting a new life cycle upon fertilization is a unique challenge faced by gametes, raising questions that involve intergenerational and transgenerational epigenetic inheritance. Therefore, we also discuss new developments that link changes during gametogenesis to early embryonic development-a rapidly growing field that promises to bring more understanding to some fundamental questions regarding metazoan development.
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13
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Venkei ZG, Yamashita YM. Emerging mechanisms of asymmetric stem cell division. J Cell Biol 2018; 217:3785-3795. [PMID: 30232100 PMCID: PMC6219723 DOI: 10.1083/jcb.201807037] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 09/06/2018] [Accepted: 09/13/2018] [Indexed: 01/10/2023] Open
Abstract
Venkei and Yamashita summarize recent advances in our understanding of asymmetric stem cell division in tissue homeostasis. The asymmetric cell division of stem cells, which produces one stem cell and one differentiating cell, has emerged as a mechanism to balance stem cell self-renewal and differentiation. Elaborate cellular mechanisms that orchestrate the processes required for asymmetric cell divisions are often shared between stem cells and other asymmetrically dividing cells. During asymmetric cell division, cells must establish asymmetry/polarity, which is guided by varying degrees of intrinsic versus extrinsic cues, and use intracellular machineries to divide in a desired orientation in the context of the asymmetry/polarity. Recent studies have expanded our knowledge on the mechanisms of asymmetric cell divisions, revealing the previously unappreciated complexity in setting up the cellular and/or environmental asymmetry, ensuring binary outcomes of the fate determination. In this review, we summarize recent progress in understanding the mechanisms and regulations of asymmetric stem cell division.
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Affiliation(s)
- Zsolt G Venkei
- Life Sciences Institute, University of Michigan, Ann Arbor, MI
| | - Yukiko M Yamashita
- Life Sciences Institute, University of Michigan, Ann Arbor, MI .,Department of Cell and Developmental Biology, Medical School, University of Michigan, Ann Arbor, MI.,Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI
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14
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Schultz MB, Sinclair DA. When stem cells grow old: phenotypes and mechanisms of stem cell aging. Development 2016; 143:3-14. [PMID: 26732838 DOI: 10.1242/dev.130633] [Citation(s) in RCA: 199] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
All multicellular organisms undergo a decline in tissue and organ function as they age. An attractive theory is that a loss in stem cell number and/or activity over time causes this decline. In accordance with this theory, aging phenotypes have been described for stem cells of multiple tissues, including those of the hematopoietic system, intestine, muscle, brain, skin and germline. Here, we discuss recent advances in our understanding of why adult stem cells age and how this aging impacts diseases and lifespan. With this increased understanding, it is feasible to design and test interventions that delay stem cell aging and improve both health and lifespan.
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Affiliation(s)
- Michael B Schultz
- Paul F. Glenn Center for the Biological Mechanisms of Aging, Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - David A Sinclair
- Paul F. Glenn Center for the Biological Mechanisms of Aging, Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
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15
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Xie J, Wooten M, Tran V, Chen BC, Pozmanter C, Simbolon C, Betzig E, Chen X. Histone H3 Threonine Phosphorylation Regulates Asymmetric Histone Inheritance in the Drosophila Male Germline. Cell 2015; 163:920-33. [PMID: 26522592 DOI: 10.1016/j.cell.2015.10.002] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 08/08/2015] [Accepted: 09/22/2015] [Indexed: 12/11/2022]
Abstract
A long-standing question concerns how stem cells maintain their identity through multiple divisions. Previously, we reported that pre-existing and newly synthesized histone H3 are asymmetrically distributed during Drosophila male germline stem cell (GSC) asymmetric division. Here, we show that phosphorylation at threonine 3 of H3 (H3T3P) distinguishes pre-existing versus newly synthesized H3. Converting T3 to the unphosphorylatable residue alanine (H3T3A) or to the phosphomimetic aspartate (H3T3D) disrupts asymmetric H3 inheritance. Expression of H3T3A or H3T3D specifically in early-stage germline also leads to cellular defects, including GSC loss and germline tumors. Finally, compromising the activity of the H3T3 kinase Haspin enhances the H3T3A but suppresses the H3T3D phenotypes. These studies demonstrate that H3T3P distinguishes sister chromatids enriched with distinct pools of H3 in order to coordinate asymmetric segregation of "old" H3 into GSCs and that tight regulation of H3T3 phosphorylation is required for male germline activity.
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Affiliation(s)
- Jing Xie
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Matthew Wooten
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Vuong Tran
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Bi-Chang Chen
- HHMI, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Caitlin Pozmanter
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Christine Simbolon
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Eric Betzig
- HHMI, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Xin Chen
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA.
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16
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Tarayrah L, Li Y, Gan Q, Chen X. Epigenetic regulator Lid maintains germline stem cells through regulating JAK-STAT signaling pathway activity. Biol Open 2015; 4:1518-27. [PMID: 26490676 PMCID: PMC4728359 DOI: 10.1242/bio.013961] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Signaling pathways and epigenetic mechanisms have both been shown to play essential roles in regulating stem cell activity. While the role of either mechanism in this regulation is well established in multiple stem cell lineages, how the two mechanisms interact to regulate stem cell activity is not as well understood. Here we report that in the Drosophila testis, an H3K4me3-specific histone demethylase encoded by little imaginal discs (lid) maintains germline stem cell (GSC) mitotic index and prevents GSC premature differentiation. Lid is required in germ cells for proper expression of the Stat92E transcription factor, the downstream effector of the Janus kinase signal transducer and activator of transcription (JAK-STAT) signaling pathway. Our findings support a germ cell autonomous role for the JAK-STAT pathway in maintaining GSCs and place Lid as an upstream regulator of this pathway. Our study provides new insights into the biological functions of a histone demethylase in vivo and sheds light on the interaction between epigenetic mechanisms and signaling pathways in regulating stem cell activities. Summary: This study provides new insights into the biological functions of a histone demethylase and sheds light on the interaction between epigenetic mechanisms and signaling pathways in regulating stem cell activities.
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Affiliation(s)
- Lama Tarayrah
- Department of Biology, 3400 North Charles Street, The Johns Hopkins University, Baltimore, MD 21218-2685, USA
| | - Yuping Li
- Department of Biology, 3400 North Charles Street, The Johns Hopkins University, Baltimore, MD 21218-2685, USA
| | - Qiang Gan
- Department of Biology, 3400 North Charles Street, The Johns Hopkins University, Baltimore, MD 21218-2685, USA
| | - Xin Chen
- Department of Biology, 3400 North Charles Street, The Johns Hopkins University, Baltimore, MD 21218-2685, USA
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17
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Feng L, Chen X. Epigenetic regulation of germ cells-remember or forget? Curr Opin Genet Dev 2015; 31:20-7. [PMID: 25930104 DOI: 10.1016/j.gde.2015.04.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 04/02/2015] [Indexed: 12/18/2022]
Abstract
Unlike somatic cells, germ cells retain the potential to reproduce an entire new organism upon fertilization. In order to accomplish the process of fertilization, germ cells undergo an extreme cellular differentiation process known as gametogenesis in order to produce morphologically and functionally distinct oocyte and sperm. In addition to changes in genetic content changes from diploid to haploid, epigenetic mechanisms that modify chromatin state without altering primary DNA sequences have profound influence on germ cell differentiation and moreover, the transgenerational effect. In this review, we will go over the most recent discoveries on epigenetic regulations in germline differentiation and transgenerational inheritance across different metazoan species.
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Affiliation(s)
- Lijuan Feng
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, United States
| | - Xin Chen
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, United States.
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18
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Shields AR, Spence AC, Yamashita YM, Davies EL, Fuller MT. The actin-binding protein profilin is required for germline stem cell maintenance and germ cell enclosure by somatic cyst cells. Development 2014; 141:73-82. [PMID: 24346697 DOI: 10.1242/dev.101931] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Specialized microenvironments, or niches, provide signaling cues that regulate stem cell behavior. In the Drosophila testis, the JAK-STAT signaling pathway regulates germline stem cell (GSC) attachment to the apical hub and somatic cyst stem cell (CySC) identity. Here, we demonstrate that chickadee, the Drosophila gene that encodes profilin, is required cell autonomously to maintain GSCs, possibly facilitating localization or maintenance of E-cadherin to the GSC-hub cell interface. Germline specific overexpression of Adenomatous Polyposis Coli 2 (APC2) rescued GSC loss in chic hypomorphs, suggesting an additive role of APC2 and F-actin in maintaining the adherens junctions that anchor GSCs to the niche. In addition, loss of chic function in the soma resulted in failure of somatic cyst cells to maintain germ cell enclosure and overproliferation of transit-amplifying spermatogonia.
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Affiliation(s)
- Alicia R Shields
- Department of Genetics, Stanford University, School of Medicine, Stanford, CA 94305, USA
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19
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Januschke J, Näthke I. Stem cell decisions: a twist of fate or a niche market? Semin Cell Dev Biol 2014; 34:116-23. [PMID: 24613913 PMCID: PMC4169664 DOI: 10.1016/j.semcdb.2014.02.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 02/24/2014] [Accepted: 02/26/2014] [Indexed: 12/28/2022]
Abstract
Extrinsic and intrinsic cues that impact on stem cell biology. The importance to establish methods that allow to compare spindle orientation measurements. Mechanisms of centrosome segregation in asymmetrically dividing cells.
Establishing and maintaining cell fate in the right place at the right time is a key requirement for normal tissue maintenance. Stem cells are at the core of this process. Understanding how stem cells balance self-renewal and production of differentiating cells is key for understanding the defects that underpin many diseases. Both, external cues from the environment and cell intrinsic mechanisms can control the outcome of stem cell division. The role of the orientation of stem cell division has emerged as an important mechanism for specifying cell fate decisions. Although, the alignment of cell divisions can dependent on spatial cues from the environment, maintaining stemness is not always linked to positioning of stem cells in a particular microenvironment or `niche'. Alternate mechanisms that could contribute to cellular memory include differential segregation of centrosomes in asymmetrically dividing cells.
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Affiliation(s)
- Jens Januschke
- Cell and Developmental Biology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
| | - Inke Näthke
- Cell and Developmental Biology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
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20
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Asymmetric distribution of histones during Drosophila male germline stem cell asymmetric divisions. Chromosome Res 2014; 21:255-69. [PMID: 23681658 DOI: 10.1007/s10577-013-9356-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
It has long been known that epigenetic changes are inheritable. However, except for DNA methylation, little is known about the molecular mechanisms of epigenetic inheritance. Many types of stem cells undergo asymmetric cell divisions to generate self-renewed stem cells and daughter cells committed for differentiation. Still, whether and how stem cells retain their epigenetic memory remain questions to be elucidated. During the asymmetric division of Drosophila male germline stem cell (GSC), our recent studies revealed that the preexisting histone 3 (H3) are selectively segregated to the GSC, whereas newly synthesized H3 deposited during DNA replication are enriched in the differentiating daughter cell. We propose a two-step model to explain this asymmetric histone distribution. First, prior to mitosis, preexisting histones and newly synthesized histones are differentially distributed at two sets of sister chromatids. Next, during mitosis, the set of sister chromatids that mainly consist of preexisting histones are segregated to GSCs, while the other set of sister chromatids enriched with newly synthesized histones are partitioned to the daughter cell committed for differentiation. In this review, we apply current knowledge about epigenetic inheritance and asymmetric cell division to inform our discussion of potential molecular mechanisms and the cellular basis underlying this asymmetric histone distribution pattern. We will also discuss whether this phenomenon contributes to the maintenance of stem cell identity and resetting chromatin structure in the other daughter cell for differentiation.
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21
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Nonrandom sister chromatid segregation of sex chromosomes in Drosophila male germline stem cells. Chromosome Res 2014; 21:243-54. [PMID: 23681657 DOI: 10.1007/s10577-013-9353-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Sister chromatids are the product of DNA replication, which is assumed to be a very precise process. Therefore, sister chromatids should be exact copies of each other. However, reports have indicated that sister chromatids are segregated nonrandomly during cell division, suggesting that sister chromatids are not the same, although their DNA sequences are the same. Researchers have speculated that stem cells may retain template strands to avoid replication-induced mutations. An alternative proposal is that cells may segregate distinct epigenetic information carried on sister chromatids. Recently, we found that Drosophila male germline stem cells segregate sister chromatids of X and Y chromosomes with a strong bias. We discuss this finding in relation to existing models for nonrandom sister chromatid segregation.
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22
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Klar AJS, Bonaduce MJ. Unbiased segregation of fission yeast chromosome 2 strands to daughter cells. Chromosome Res 2014; 21:297-309. [PMID: 23681661 DOI: 10.1007/s10577-013-9352-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The base complementarity feature (Watson and Crick in Nature 171(4356):737-738, 1953) and the rule of semi-conservative mode of DNA replication (Messelson and Stahl in Proc Natl Acad Sci U S A 44:671-682, 1958) dictate that two identical replicas of the parental chromosome are produced during replication. In principle, the inherent strand sequence differences could generate nonequivalent daughter chromosome replicas if one of the two strands were epigenetically imprinted during replication to effect silencing/expression of developmentally important genes. Indeed, inheritance of such a strand- and site-specific imprint confers developmental asymmetry to fission yeast sister cells by a phenomenon called mating/cell-type switching. Curiously, location of DNA strands with respect to each other at the centromere is fixed, and as a result, their selected segregation to specific sister chromatid copies occurs in eukaryotic cells. The yeast system provides a unique opportunity to determine the significance of such biased strand distribution to sister chromatids. We determined whether the cylindrical-shaped yeast cell distributes the specific chromosomal strand to the same cellular pole in successive cycles of cell division. By observing the pattern of recurrent mating-type switching in progenies of individual cells by microscopic analyses, we found that chromosome 2 strands are distributed by the random mode in successive cell divisions. We also exploited unusual "hotspot" recombination features of this system to investigate whether there is selective segregation of strands such that oldest Watson-containing strands co-segregate in the diploid cell at mitosis. Our data suggests that chromosome 2 strands are segregated independently to those of the homologous chromosome.
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Affiliation(s)
- Amar J S Klar
- Gene Regulation and Chromosome Biology Laboratory, National Cancer Institute, Center for National Cancer Research, National Institutes of Health, Building 539, Room 154, Frederick, MD 21702-1201, USA.
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23
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Waghmare SK, Tumbar T. Adult hair follicle stem cells do not retain the older DNA strands in vivo during normal tissue homeostasis. Chromosome Res 2014; 21:203-12. [PMID: 23681654 DOI: 10.1007/s10577-013-9355-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Tissue stem cells have been proposed to segregate the chromosomes asymmetrically (in a non-random manner), thereby retaining preferentially the older "immortal" DNA strands bearing the stemness characteristics into one daughter cell, whereas the newly synthesized strands are segregated to the other daughter cell that will commit to differentiation. Moreover, this non-random segregation would protect the stem cell genome from accumulating multiple mutations during repeated DNA replication. This long-standing hypothesis remains an active subject of study due to conflicting results for some systems and lack of consistency among different tissue stem cell populations. In this review, we will focus on work done in the hair follicle, which is one of the best-understood vertebrate tissue stem cell system to date. In cell culture analysis of paired cultured keratinocytes derived from hair follicle, stem cells suggested a non-random segregation of chromosome with respect to the older DNA strand. In vivo, the hair follicle stem cells appear to self-renew and differentiate at different phases of their homeostatic cycle. The fate decisions occur in quiescence when some stem cells migrate out of their niche and commit to differentiation without self-renewal. The stem cells left behind in the niche self-renew symmetrically and randomly segregate the chromosomes at each division, making more stem cells. This model seems to apply to at least a few other vertebrate tissue stem cells in vivo.
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Affiliation(s)
- Sanjeev K Waghmare
- Advanced Centre for Treatment, Research and Education in Cancer ACTREC, Tata Memorial Centre, Navi Mumbai, 410210, India.
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24
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Liu W, Jeganathan G, Amiri S, Morgan KM, Ryan BM, Pine SR. Asymmetric segregation of template DNA strands in basal-like human breast cancer cell lines. Mol Cancer 2013; 12:139. [PMID: 24238140 PMCID: PMC3866575 DOI: 10.1186/1476-4598-12-139] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 11/11/2013] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND AND METHODS Stem or progenitor cells from healthy tissues have the capacity to co-segregate their template DNA strands during mitosis. Here, we set out to test whether breast cancer cell lines also possess the ability to asymmetrically segregate their template DNA strands via non-random chromosome co-segregation, and whether this ability correlates with certain properties attributed to breast cancer stem cells (CSCs). We quantified the frequency of asymmetric segregation of template DNA strands in 12 human breast cancer cell lines, and correlated the frequency to molecular subtype, CD44+/CD24-/lo phenotype, and invasion/migration ability. We tested if co-culture with human mesenchymal stem cells, which are known to increase self-renewal, can alter the frequency of asymmetric segregation of template DNA in breast cancer. RESULTS We found a positive correlation between asymmetric segregation of template DNA and the breast cancer basal-like and claudin-low subtypes. There was an inverse correlation between asymmetric segregation of template DNA and Her2 expression. Breast cancer samples with evidence of asymmetric segregation of template DNA had significantly increased invasion and borderline significantly increased migration abilities. Samples with high CD44+/CD24-/lo surface expression were more likely to harbor a consistent population of cells that asymmetrically segregated its template DNA; however, symmetric self-renewal was enriched in the CD44+/CD24-/lo population. Co-culturing breast cancer cells with human mesenchymal stem cells expanded the breast CSC pool and decreased the frequency of asymmetric segregation of template DNA. CONCLUSIONS Breast cancer cells within the basal-like subtype can asymmetrically segregate their template DNA strands through non-random chromosome segregation. The frequency of asymmetric segregation of template DNA can be modulated by external factors that influence expansion or self-renewal of CSC populations. Future studies to uncover the underlying mechanisms driving asymmetric segregation of template DNA and dictating cell fate at the time of cell division may explain how CSCs are maintained in tumors.
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Affiliation(s)
| | | | | | | | | | - Sharon R Pine
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, 195 Little Albany Street, New Brunswick, New Jersey, USA.
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25
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Abstract
The immortal strand hypothesis proposes that stem cells retain a template copy of genomic DNA (i.e. an 'immortal strand') to avoid replication-induced mutations. An alternative hypothesis suggests that certain cells segregate sister chromatids non-randomly to transmit distinct epigenetic information. However, this area of research has been highly controversial, with conflicting data even from the same cell types. Moreover, historically, the same term of 'non-random sister chromatid segregation' or 'biased sister chromatid segregation' has been used to indicate distinct biological processes, generating a confusion in the biological significance and potential mechanism of each phenomenon. Here, we discuss the models of non-random sister chromatid segregation, and we explore the strengths and limitations of the various techniques and experimental model systems used to study this question. We also describe our recent study on Drosophila male germline stem cells, where sister chromatids of X and Y chromosomes are segregated non-randomly during cell division. We aim to integrate the existing evidence to speculate on the underlying mechanisms and biological relevance of this long-standing observation on non-random sister chromatid segregation.
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Affiliation(s)
- Swathi Yadlapalli
- Life Sciences Institute, Center for Stem Cell Biology, University of Michigan, Ann Arbor, MI 48109, USA
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26
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Salzmann V, Inaba M, Cheng J, Yamashita YM. Lineage tracing quantification reveals symmetric stem cell division in Drosophila male germline stem cells. Cell Mol Bioeng 2013; 6:441-448. [PMID: 24465278 DOI: 10.1007/s12195-013-0295-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In the homeostatic state, adult stem cells divide either symmetrically to increase the stem cell number to compensate stem cell loss, or asymmetrically to maintain the population while producing differentiated cells. We have investigated the mode of stem cell division in the testes of Drosophila melanogaster by lineage tracing and confirm the presence of symmetric stem cell division in this system. We found that the rate of symmetric division is limited to 1-2% of total germline stem cell (GSC) divisions, but it increases with expression of a cell adhesion molecule, E-cadherin, or a regulator of the actin cytoskeleton, Moesin, which may modulate adhesiveness of germ cells to the stem cell niche. Our results indicate that the decision regarding asymmetric vs. symmetric division is a dynamically regulated process that contributes to tissue homeostasis, responding to the needs of the tissue.
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Affiliation(s)
- Viktoria Salzmann
- Life Sciences Institute, Department of Cell and Developmental Biology, University of Michigan Ann Arbor
| | - Mayu Inaba
- Life Sciences Institute, Department of Cell and Developmental Biology, University of Michigan Ann Arbor
| | - Jun Cheng
- Department of Bioengineering, University of Illinois at Chicago, 851 S Morgan Street, Chicago IL 60607
| | - Yukiko M Yamashita
- Life Sciences Institute, Department of Cell and Developmental Biology, University of Michigan Ann Arbor
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27
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Charville GW, Rando TA. A sexy spin on nonrandom chromosome segregation. Cell Stem Cell 2013; 12:641-3. [PMID: 23746972 DOI: 10.1016/j.stem.2013.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Nonrandom chromosome segregation is an intriguing phenomenon linked to certain asymmetric stem cell divisions. In a recent report in Nature, Yadlapalli and Yamashita (2013) observe nonrandom segregation of X and Y chromosomes in Drosophila germline stem cells and shed light on the complex mechanisms of this fascinating process.
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Affiliation(s)
- Gregory W Charville
- Paul F. Glenn Laboratories for the Biology of Aging, Stanford University School of Medicine, Stanford, CA 94305, USA
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28
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Biased DNA segregation in Drosophila male germline stem cells. Semin Cell Dev Biol 2013; 24:618-26. [PMID: 23707893 DOI: 10.1016/j.semcdb.2013.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 05/02/2013] [Indexed: 01/09/2023]
Abstract
The immortal strand hypothesis, which emerged four decades ago, proposes that certain cells retain a template copy of chromosomal DNA to protect against replication-induced mutations. As the interest in stem cells rose in recent years, researchers speculated that stem cells, which must maintain proliferative capacity throughout the life of the organism, may be the population that most needs the strong protection afforded by immortal strand segregation. Alternative hypotheses have also been proposed to explain observed non-random sister chromatid segregation. We recently found that Drosophila male germline stem cells segregate sister chromatids non-randomly, but such bias was limited to the sex chromosomes. Interestingly, the biased segregation does not lead to immortal strand segregation. We will discuss the implications of this observation and molecular mechanisms, which might be applicable to non-random sister chromatid segregation in other systems as well.
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29
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Abstract
The semi-conservative nature of DNA replication has suggested that identical DNA molecules within chromatids are inherited by daughter cells after cell division. Numerous reports of non-random DNA segregation in prokaryotes and eukaryotes suggest that this is not always the case, and that epigenetic marks on chromatids, if not the individual DNA strands themselves, could have distinct signatures. Their selective distribution to daughter cells provides a novel mechanism for gene and cell fate regulation by segregating chromatids asymmetrically. Here we highlight some examples and potential mechanisms that can regulate this process. We propose that cellular asymmetry is inherently present during each cell division, and that it provides an opportunity during each cell cycle for moderating cell fates.
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Affiliation(s)
- Siham Yennek
- Institut Pasteur, Stem Cells & Development, Department of Developmental & Stem Cell Biology, CNRS URA 2578, 25 rue du Dr. Roux, Paris F-75015, France
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30
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Strand-seq: a unifying tool for studies of chromosome segregation. Semin Cell Dev Biol 2013; 24:643-52. [PMID: 23665005 DOI: 10.1016/j.semcdb.2013.04.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 04/30/2013] [Indexed: 12/21/2022]
Abstract
Non random segregation of sister chromatids has been implicated to help specify daughter cell fate (the Silent Sister Hypothesis [1]) or to protect the genome of long-lived stem cells (the Immortal Strand Hypothesis [2]). The idea that sister chromatids are non-randomly segregated into specific daughter cells is only marginally supported by data in sporadic and often contradictory studies. As a result, the field has moved forward rather slowly. The advent of being able to directly label and differentiate sister chromatids in vivo using fluorescence in situ hybridization [3] was a significant advance for such studies. However, this approach is limited by the need for large tracks of unidirectional repeats on chromosomes and the reliance on quantitative imaging of fluorescent probes and rigorous statistical analysis to discern between the two competing hypotheses. A novel method called Strand-seq which uses next-generation sequencing to assay sister chromatid inheritance patterns independently for each chromosome [4] offers a comprehensive approach to test for non-random segregation. In addition Strand-seq enables studies on the deposition of chromatin marks in relation to DNA replication. This method is expected to help unify the field by testing previous claims of non-random segregation in an unbiased way in many model systems in vitro and in vivo.
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31
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Yadlapalli S, Yamashita YM. Chromosome-specific nonrandom sister chromatid segregation during stem-cell division. Nature 2013; 498:251-4. [PMID: 23644460 PMCID: PMC3711665 DOI: 10.1038/nature12106] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Accepted: 03/20/2013] [Indexed: 01/07/2023]
Abstract
Adult stem cells undergo asymmetric cell division to self-renew and give rise to differentiated cells that comprise mature tissue1. Sister chromatids may be distinguished and segregated non-randomly in asymmetrically dividing stem cells2, although the underlying mechanism and the purpose it may serve remain elusive. We developed the CO-FISH (chromosome orientation fluorescence in situ hybridization) technique3 with single-chromosome resolution and show that sister chromatids of X and Y chromosomes, but not autosomes, are segregated non-randomly during asymmetric divisions of Drosophila male germline stem cells (GSCs). This provides the first direct evidence that two sister chromatids containing identical genetic information can be distinguished and segregated non-randomly during asymmetric stem cell divisions. We further show that the centrosome, SUN-KASH nuclear envelope proteins, and Dnmt2 are required for non-random sister chromatid segregation. Our data suggest that the information on X and Y chromosomes that enables non-random segregation is primed during gametogenesis in the parents. Moreover, we show that sister chromatid segregation is randomized in GSC overproliferation and dedifferentiated GSCs. We propose that non-random sister chromatid segregation may serve to transmit distinct information carried on two sister chromatids to the daughters of asymmetrically dividing stem cells.
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Affiliation(s)
- Swathi Yadlapalli
- Life Sciences Institute, Center for Stem Cell Biology, University of Michigan, Ann Arbor, Michigan 48109, USA.
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32
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Tran V, Lim C, Xie J, Chen X. Asymmetric division of Drosophila male germline stem cell shows asymmetric histone distribution. Science 2012; 338:679-82. [PMID: 23118191 DOI: 10.1126/science.1226028] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Stem cells can self-renew and generate differentiating daughter cells. It is not known whether these cells maintain their epigenetic information during asymmetric division. Using a dual-color method to differentially label "old" versus "new" histones in Drosophila male germline stem cells (GSCs), we show that preexisting canonical H3, but not variant H3.3, histones are selectively segregated to the GSC, whereas newly synthesized histones incorporated during DNA replication are enriched in the differentiating daughter cell. The asymmetric histone distribution occurs in GSCs but not in symmetrically dividing progenitor cells. Furthermore, if GSCs are genetically manipulated to divide symmetrically, this asymmetric mode is lost. This work suggests that stem cells retain preexisting canonical histones during asymmetric cell divisions, probably as a mechanism to maintain their unique molecular properties.
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Affiliation(s)
- Vuong Tran
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
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33
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Abstract
Germline stem cells are key to genome transmission to future generations. Over recent years, there have been numerous insights into the regulatory mechanisms that govern both germ cell specification and the maintenance of the germline in adults. Complex regulatory interactions with both the niche and the environment modulate germline stem cell function. This perspective highlights some examples of this regulation to illustrate the diversity and complexity of the mechanisms involved.
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Affiliation(s)
- Ruth Lehmann
- Howard Hughes Medical Institute; Skirball Institute, The Helen L. and Martin S. Kimmel Center for Stem Cell Biology, Department of Cell Biology, New York University School of Medicine, 540 First Avenue, New York, NY 10016, USA.
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34
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Sister chromatids segregate at mitosis without mother-daughter bias in Saccharomyces cerevisiae. Genetics 2012; 192:1553-7. [PMID: 23051643 DOI: 10.1534/genetics.112.145680] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
There is evidence accumulating for nonrandom segregation of one or more chromosomes during mitosis in different cell types. We use cell synchrony and two methods to show that all chromatids of budding yeast segregate randomly and that there is no mother-daughter bias with respect to Watson and Crick-containing strands of DNA.
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35
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Chambers I, Schroeder T. Stem cell powwow in Squaw Valley. Development 2012; 139:2457-61. [PMID: 22736242 DOI: 10.1242/dev.079475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Keystone Symposium entitled 'The Life of a Stem Cell: from Birth to Death' was held at Squaw Valley, CA, USA in March 2012. The meeting brought together researchers from across the world and showcased the most recent developments in stem cell research. Here, we review the proceedings at this meeting and discuss the major advances in fundamental and applied stem cell biology that emerged.
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Affiliation(s)
- Ian Chambers
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, 5 Little France Drive, Edinburgh EH16 4UU, UK.
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36
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Matunis EL, Stine RR, de Cuevas M. Recent advances in Drosophila male germline stem cell biology. SPERMATOGENESIS 2012; 2:137-144. [PMID: 23087833 PMCID: PMC3469437 DOI: 10.4161/spmg.21763] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The ability of stem cells to divide asymmetrically to produce both self-renewing and differentiating daughter cells sustains many adult tissues, but germline stem cells (GSCs) are unique among stem cells as they perpetuate the genome of the species. The cellular and molecular mechanisms regulating most mammalian stem cells in their endogenous local microenvironments, or niches, are quite challenging to study. However, studies of stem cell niches such as those found in the Drosophila gonads have proven very useful. In these tissues, GSCs are housed in a readily identifiable niche, and the ability to genetically manipulate these cells and their neighbors has uncovered several fundamental mechanisms that are relevant to stem cells more generally. Here, we summarize recent work on the regulation of GSCs in the Drosophila testis niche by intercellular signals, and on the intracellular mechanisms that cooperate with these signals to ensure the survival of the germline. This review focuses on GSCs within the adult Drosophila testis; somatic stem cells in this tissue are reviewed by Zoller and Schulz in this issue.(1) For a review of the testis niche as a whole, see de Cuevas and Matunis,(2) and for more comprehensive reviews of the Drosophila testis, refer to Fuller(3) and Davies and Fuller.(4).
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Affiliation(s)
- Erika L. Matunis
- Department of Cell Biology; Johns Hopkins University School of Medicine; Baltimore, MD USA
| | - Rachel R. Stine
- Department of Cell Biology; Johns Hopkins University School of Medicine; Baltimore, MD USA
| | - Margaret de Cuevas
- Department of Cell Biology; Johns Hopkins University School of Medicine; Baltimore, MD USA
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37
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Pelletier L, Yamashita YM. Centrosome asymmetry and inheritance during animal development. Curr Opin Cell Biol 2012; 24:541-6. [PMID: 22683192 DOI: 10.1016/j.ceb.2012.05.005] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 05/23/2012] [Indexed: 01/15/2023]
Abstract
The centrosome is a subcellular organelle that is responsible for the majority of microtubule organization. Through this ability, the centrosome is involved in cell division, migration, and polarization. Recent studies have revealed intriguing asymmetries between mother and daughter centrioles as well as between mother and daughter centrosomes, and the involvement of such asymmetries in multiple cellular and developmental processes. This review aims to summarize recent discoveries on such asymmetries in centrioles/centrosomes and the potential implication of their inheritance patterns during cell division and development.
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Affiliation(s)
- Laurence Pelletier
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada.
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38
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Xin HW, Hari DM, Mullinax JE, Ambe CM, Koizumi T, Ray S, Anderson AJ, Wiegand GW, Garfield SH, Thorgeirsson SS, Avital I. Tumor-initiating label-retaining cancer cells in human gastrointestinal cancers undergo asymmetric cell division. Stem Cells 2012; 30:591-8. [PMID: 22331764 PMCID: PMC3492937 DOI: 10.1002/stem.1061] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Label-retaining cells (LRCs) have been proposed to represent adult tissue stem cells. LRCs are hypothesized to result from either slow cycling or asymmetric cell division (ACD). However, the stem cell nature and whether LRC undergo ACD remain controversial. Here, we demonstrate label-retaining cancer cells (LRCCs) in several gastrointestinal (GI) cancers including fresh surgical specimens. Using a novel method for isolation of live LRCC, we demonstrate that a subpopulation of LRCC is actively dividing and exhibits stem cells and pluripotency gene expression profiles. Using real-time confocal microscopic cinematography, we show live LRCC undergoing asymmetric nonrandom chromosomal cosegregation LRC division. Importantly, LRCCs have greater tumor-initiating capacity than non-LRCCs. Based on our data and that cancers develop in tissues that harbor normal-LRC, we propose that LRCC might represent a novel population of GI stem-like cancer cells. LRCC may provide novel mechanistic insights into the biology of cancer and regenerative medicine and present novel targets for cancer treatment.
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Affiliation(s)
- Hong-Wu Xin
- Gastrointestinal and Hepatobiliary Malignancies Section, Surgery Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Danielle M. Hari
- Gastrointestinal and Hepatobiliary Malignancies Section, Surgery Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - John E. Mullinax
- Gastrointestinal and Hepatobiliary Malignancies Section, Surgery Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Chenwi M. Ambe
- Gastrointestinal and Hepatobiliary Malignancies Section, Surgery Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Tomotake Koizumi
- Gastrointestinal and Hepatobiliary Malignancies Section, Surgery Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Satyajit Ray
- Gastrointestinal and Hepatobiliary Malignancies Section, Surgery Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Andrew J. Anderson
- Gastrointestinal and Hepatobiliary Malignancies Section, Surgery Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Gordon W. Wiegand
- Gastrointestinal and Hepatobiliary Malignancies Section, Surgery Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Susan H. Garfield
- Laboratory for Experimental Carcinogenesis, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Snorri S. Thorgeirsson
- Laboratory for Experimental Carcinogenesis, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Itzhak Avital
- Gastrointestinal and Hepatobiliary Malignancies Section, Surgery Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
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Affiliation(s)
- Jesse L Mull
- Stem Cell Institute, Paul and Sheila Wellstone Muscular Dystrophy Center, and Department of Neurology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Atsushi Asakura
- Stem Cell Institute, Paul and Sheila Wellstone Muscular Dystrophy Center, and Department of Neurology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
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Yadlapalli S, Cheng J, Yamashita YM. Reply to: Overlooked areas need attention for sound evaluation of DNA strand inheritance patterns in Drosophila male germline stem cells. J Cell Sci 2011. [DOI: 10.1242/jcs.097949] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Swathi Yadlapalli
- Life Sciences Institute, Center for Stem Cell Biology, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Cell and Developmental Biology Medical School, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jun Cheng
- Department of Bioengineering, University of Illinois, Chicago, 851 S Morgan Street, 218 SEO, Chicago, IL 60607-7052, USA
| | - Yukiko M. Yamashita
- Life Sciences Institute, Center for Stem Cell Biology, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Cell and Developmental Biology Medical School, University of Michigan, Ann Arbor, MI 48109, USA
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109, USA
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Yadlapalli S, Yamashita YM. Spindle positioning in the stem cell niche. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2011; 1:215-30. [DOI: 10.1002/wdev.16] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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42
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Seandel M, Eggan K. Stem Cells: Doing Some Heavy Lifting at ISSCR 2011. Cell Stem Cell 2011. [DOI: 10.1016/j.stem.2011.09.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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43
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Yadlapalli S, Cheng J, Yamashita Y. Drosophila male germline stem cells do not asymmetrically segregate chromosome strands. Development 2011. [DOI: 10.1242/dev.066407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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