101
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Abstract
During the development of the mammalian central nervous system, neural stem cells and their derivative progenitor cells generate neurons by asymmetric and symmetric divisions. The proliferation versus differentiation of these cells and the type of division are closely linked to their epithelial characteristics, notably, their apical-basal polarity and cell-cycle length. Here, we discuss how these features change during development from neuroepithelial to radial glial cells, and how this transition affects cell fate and neurogenesis.
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Affiliation(s)
- Magdalena Götz
- Institute for Stem Cell Research, GSF-National Research Center for Environment and Health, Ingolstädter Landstrasse 1, D-85764 Neuherberg/Munich, Germany.
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102
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Marzesco AM, Janich P, Wilsch-Bräuninger M, Dubreuil V, Langenfeld K, Corbeil D, Huttner WB. Release of extracellular membrane particles carrying the stem cell marker prominin-1 (CD133) from neural progenitors and other epithelial cells. J Cell Sci 2005; 118:2849-58. [PMID: 15976444 DOI: 10.1242/jcs.02439] [Citation(s) in RCA: 354] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Apical plasma membrane constituents of mammalian neural stem/progenitor cells have recently been implicated in maintaining their stem/progenitor cell state. Here, we report that in the developing embryonic mouse brain, the fluid in the lumen of the neural tube contains membrane particles carrying the stem cell marker prominin-1 (CD133), a pentaspan membrane protein found on membrane protrusions of the apical surface of neuroepithelial cells. Two size classes of prominin-1-containing membrane particles were observed in the ventricular fluid: approximately 600-nm particles, referred to as P2 particles, and 50-80-nm vesicles, referred to as P4 particles. The P2 and P4 particles appeared in the ventricular fluid at the very onset and during the early phase of neurogenesis, respectively. Concomitant with their appearance, the nature of the prominin-1-containing apical plasma membrane protrusions of neuroepithelial cells changed, in that microvilli were lost and large pleiomorphic protuberances appeared. P4 particles were found in various body fluids of adult humans, including saliva, seminal fluid and urine, and were released by the epithelial model cell line Caco-2 upon differentiation. Importantly, P4 particles were distinct from exosomes. Our results demonstrate the widespread occurrence of a novel class of extracellular membrane particles containing proteins characteristic of stem cells, and raise the possibility that the release of the corresponding membrane subdomains from the apical surface of neural progenitors and other epithelial cells may have a role in tissue development and maintenance. Moreover, the presence of prominin-1-containing membrane particles in human body fluids may provide the basis for a protein-based diagnosis of certain diseases.
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Affiliation(s)
- Anne-Marie Marzesco
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
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103
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Emery G, Hutterer A, Berdnik D, Mayer B, Wirtz-Peitz F, Gaitan MG, Knoblich JA. Asymmetric Rab 11 endosomes regulate delta recycling and specify cell fate in the Drosophila nervous system. Cell 2005; 122:763-73. [PMID: 16137758 DOI: 10.1016/j.cell.2005.08.017] [Citation(s) in RCA: 250] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2005] [Revised: 06/22/2005] [Accepted: 08/16/2005] [Indexed: 01/15/2023]
Abstract
Drosophila sensory organ precursor (SOP) cells are a well-studied model system for asymmetric cell division. During SOP division, the determinants Numb and Neuralized segregate into the pIIb daughter cell and establish a distinct cell fate by regulating Notch/Delta signaling. Here, we describe a Numb- and Neuralized-independent mechanism that acts redundantly in cell-fate specification. We show that trafficking of the Notch ligand Delta is different in the two daughter cells. In pIIb, Delta passes through the recycling endosome which is marked by Rab 11. In pIIa, however, the recycling endosome does not form because the centrosome fails to recruit Nuclear fallout, a Rab 11 binding partner that is essential for recycling endosome formation. Using a mammalian cell culture system, we demonstrate that recycling endosomes are essential for Delta activity. Our results suggest that cells can regulate signaling pathways and influence their developmental fate by inhibiting the formation of individual endocytic compartments.
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Affiliation(s)
- Gregory Emery
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Dr. Bohr Gasse 3-5, 1030 Vienna, Austria
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104
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Zigman M, Cayouette M, Charalambous C, Schleiffer A, Hoeller O, Dunican D, McCudden CR, Firnberg N, Barres BA, Siderovski DP, Knoblich JA. Mammalian Inscuteable Regulates Spindle Orientation and Cell Fate in the Developing Retina. Neuron 2005; 48:539-45. [PMID: 16301171 DOI: 10.1016/j.neuron.2005.09.030] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2005] [Revised: 09/06/2005] [Accepted: 09/28/2005] [Indexed: 10/25/2022]
Abstract
During mammalian neurogenesis, progenitor cells can divide with the mitotic spindle oriented parallel or perpendicular to the surface of the neuroepithelium. Perpendicular divisions are more likely to be asymmetric and generate one progenitor and one neuronal precursor. Whether the orientation of the mitotic spindle actually determines their asymmetric outcome is unclear. Here, we characterize a mammalian homolog of Inscuteable (mInsc), a key regulator of spindle orientation in Drosophila. mInsc is expressed temporally and spatially in a manner that suggests a role in orienting the mitotic spindle in the developing nervous system. Using retroviral RNAi in rat retinal explants, we show that downregulation of mInsc inhibits vertical divisions. This results in enhanced proliferation, consistent with a higher frequency of symmetric divisions generating two proliferating cells. Our results suggest that the orientation of neural progenitor divisions is important for cell fate specification in the retina and determines their symmetric or asymmetric outcome.
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Affiliation(s)
- Mihaela Zigman
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Dr Bohr Gasse 3-5, 1030 Vienna, Austria
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105
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Shi S, Stahl M, Lu L, Stanley P. Canonical Notch signaling is dispensable for early cell fate specifications in mammals. Mol Cell Biol 2005; 25:9503-8. [PMID: 16227600 PMCID: PMC1265842 DOI: 10.1128/mcb.25.21.9503-9508.2005] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2005] [Revised: 08/03/2005] [Accepted: 08/13/2005] [Indexed: 01/25/2023] Open
Abstract
The canonical Notch signaling pathway mediated by Delta- and Jagged-like Notch ligands determines a variety of cell fates in metazoa. In Caenorhabditis elegans and sea urchins, canonical Notch signaling is essential for different cell fate specifications during early embryogenesis or the formation of endoderm, mesoderm, or ectoderm germ layers. Transcripts of Notch signaling pathway genes are present during mouse blastogenesis, suggesting that the canonical Notch signaling pathway may also function in early mammalian development. To test this directly, we used conditional deletion in oocytes carrying a ZP3Cre recombinase transgene to generate mouse embryos lacking both maternal and zygotic protein O-fucosyltransferase 1, a cell-autonomous and essential component of canonical Notch receptor signaling. Homozygous mutant embryos derived from eggs lacking Pofut1 gene transcripts developed indistinguishably from the wild type until approximately embryonic day 8.0, a postgastrulation stage after the formation of the three germ layers. Thus, in contrast to the case with C. elegans and sea urchins, canonical Notch signaling is not required in mammals for earliest cell fate specifications or for formation of the three germ layers. The use of canonical Notch signaling for early cell fate specifications by lower organisms may represent co-option of a regulatory pathway originally used later in development by all metazoa.
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Affiliation(s)
- Shaolin Shi
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY 10461, USA
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106
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Huttner WB, Kosodo Y. Symmetric versus asymmetric cell division during neurogenesis in the developing vertebrate central nervous system. Curr Opin Cell Biol 2005; 17:648-57. [PMID: 16243506 DOI: 10.1016/j.ceb.2005.10.005] [Citation(s) in RCA: 197] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Accepted: 10/03/2005] [Indexed: 01/23/2023]
Abstract
The type and number of cell divisions of neuronal progenitors determine the number of neurons generated during the development of the vertebrate central nervous system. Over the past several years, there has been substantial progress in characterizing the various kinds of neuronal progenitors and the types of symmetric and asymmetric divisions they undergo. The understanding of the cell-biological basis of symmetric versus asymmetric progenitor cell division has been consolidated, and the molecular machinery controlling these divisions is beginning to be unravelled. Other recent advances include comparative studies of brain development in rodents and primates, as well as the identification of gene mutations in humans that affect the balance between the various types of cell division of neuronal progenitors.
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Affiliation(s)
- Wieland B Huttner
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstr. 108, D-01307 Dresden, Germany.
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107
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Poggi L, Zolessi FR, Harris WA. Time-lapse analysis of retinal differentiation. Curr Opin Cell Biol 2005; 17:676-81. [PMID: 16226448 DOI: 10.1016/j.ceb.2005.09.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Accepted: 09/29/2005] [Indexed: 11/22/2022]
Abstract
The availability of new vital markers and the improvements in time-lapse video microscopy have increased our ability to observe developmental events in the retina while they are happening. Using this approach, advances have been made in the understanding of important issues such as how division patterns relate to cell fate determination, how post-mitotic progenitors reach their correct retinal layers, and finally, how retinal ganglion cell axons navigate out of the retina and to their final targets in the midbrain.
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Affiliation(s)
- Lucia Poggi
- Department of Anatomy, Downing St, Cambridge University, Cambridge CB2 3DY, UK
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108
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Wodarz A. Molecular control of cell polarity and asymmetric cell division in Drosophila neuroblasts. Curr Opin Cell Biol 2005; 17:475-81. [PMID: 16099639 DOI: 10.1016/j.ceb.2005.08.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Accepted: 08/02/2005] [Indexed: 12/29/2022]
Abstract
In the embryonic central nervous system of the fruit fly Drosophila, most neurons and glial cells are generated by asymmetric division of neural stem cells called neuroblasts. Several genes have been identified that are required for the establishment of neuroblast polarity, for the asymmetric segregation of cell fate determinants and for the proper orientation and geometry of the mitotic spindle. However, little was known about the interactions between these genes and their respective gene products. It has emerged that most of the relevant proteins are assembled into three major protein complexes whose molecular interactions are conserved in evolution.
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Affiliation(s)
- Andreas Wodarz
- Abteilung Stammzellbiologie, Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany.
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109
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110
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Karcavich RE. Generating neuronal diversity in the Drosophila central nervous system: a view from the ganglion mother cells. Dev Dyn 2005; 232:609-16. [PMID: 15704126 DOI: 10.1002/dvdy.20273] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The generation of cellular diversity in the developing embryonic central nervous system of Drosophila melanogaster requires the precise orchestration of several convergent molecular and cellular mechanisms. Most reviews have focused on the formation and specification of neuroblasts (NBs), the putative neural stem cell in the Drosophila central nervous system. NBs divide asymmetrically to regenerate themselves and produce a secondary precursor cell called a ganglion mother cell (GMC), which divides to produce neurons and glia. Historically, our understanding of GMC specification has arisen from work involving asymmetric localization of intrinsic factors in the NB and GMC. However, recent information on NB lineages has revealed additional intrinsic factors that specify general and specific GMC fates. This review addresses what has been revealed about these intrinsic cues with regard to GMC specification. For example, Prospero, an asymmetrically localized determinant, plays a general role to enable GMC development and to distinguish GMCs from NBs. In contrast, the temporal gene cascade functions within NB lineages to ensure that each GMC in a lineage acquires a different fate. Two different mechanisms used to make the progeny of GMCs different will also be discussed. One is a generic mechanism, regulated by Notch and Numb, that allows sibling cells to adopt different fates. The other mechanism involves genes, such as even-skipped and klumpfuss that specify the fate of individual GMCs. All of these mechanisms converge within a GMC to bestow upon it a unique fate.
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Affiliation(s)
- Rachel E Karcavich
- Indiana University Center for Regenerative Biology and Medicine / Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, Indiana 46202, USA.
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111
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Yu F, Wang H, Qian H, Kaushik R, Bownes M, Yang X, Chia W. Locomotion defects, together with Pins, regulates heterotrimeric G-protein signaling during Drosophila neuroblast asymmetric divisions. Genes Dev 2005; 19:1341-53. [PMID: 15937221 PMCID: PMC1142557 DOI: 10.1101/gad.1295505] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2005] [Accepted: 04/19/2005] [Indexed: 01/18/2023]
Abstract
Heterotrimeric G proteins mediate asymmetric division of Drosophila neuroblasts. Free Gbetagamma appears to be crucial for the generation of an asymmetric mitotic spindle and consequently daughter cells of distinct size. However, how Gbetagamma is released from the inactive heterotrimer remains unclear. Here we show that Locomotion defects (Loco) interacts and colocalizes with Galphai and, through its GoLoco motif, acts as a guanine nucleotide dissociation inhibitor (GDI) for Galphai. Simultaneous removal of the two GoLoco motif proteins, Loco and Pins, results in defects that are essentially indistinguishable from those observed in Gbeta13F or Ggamma1 mutants, suggesting that Loco and Pins act synergistically to release free Gbetagamma in neuroblasts. Furthermore, the RGS domain of Loco can also accelerate the GTPase activity of Galphai to regulate the equilibrium between the GDP- and the GTP-bound forms of Galphai. Thus, Loco can potentially regulate heterotrimeric G-protein signaling via two distinct modes of action during Drosophila neuroblast asymmetric divisions.
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Affiliation(s)
- Fengwei Yu
- Temasek Lifesciences Laboratory and Department of Biological Sciences, National University of Singapore.
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112
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Sun Y, Goderie SK, Temple S. Asymmetric distribution of EGFR receptor during mitosis generates diverse CNS progenitor cells. Neuron 2005; 45:873-86. [PMID: 15797549 DOI: 10.1016/j.neuron.2005.01.045] [Citation(s) in RCA: 166] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2004] [Revised: 12/23/2004] [Accepted: 01/27/2005] [Indexed: 11/25/2022]
Abstract
It has been debated whether asymmetric distribution of cell surface receptors during mitosis could generate asymmetric cell divisions by yielding daughters with different environmental responsiveness and, thus, different fates. We have found that in mouse embryonic forebrain ventricular and subventricular zones, the EGFR can distribute asymmetrically during mitosis in vivo and in vitro. This occurs during divisions yielding two Nestin+ progenitor cells, via an actin-dependent mechanism. The resulting sibling progenitor cells respond differently to EGFR ligand in terms of migration and proliferation. Moreover, they express different phenotypic markers: the EGFRhigh daughter usually has radial glial/astrocytic markers, while its EGFRlow sister lacks them, indicating fate divergence. Lineage trees of cultured cortical glioblasts reveal repeated EGFR asymmetric distribution, and asymmetric divisions underlie formation of oligodendrocytes and astrocytes in clones. These data suggest that asymmetric EGFR distribution contributes to forebrain development by creating progenitors with different proliferative, migratory, and differentiation responses to ligand.
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Affiliation(s)
- Yu Sun
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, New York 12208, USA
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113
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von Stein W, Ramrath A, Grimm A, Müller-Borg M, Wodarz A. Direct association of Bazooka/PAR-3 with the lipid phosphatase PTEN reveals a link between the PAR/aPKC complex and phosphoinositide signaling. Development 2005; 132:1675-86. [PMID: 15743877 DOI: 10.1242/dev.01720] [Citation(s) in RCA: 167] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cell polarity in Drosophila epithelia, oocytes and neuroblasts is controlled by the evolutionarily conserved PAR/aPKC complex, which consists of the serine-threonine protein kinase aPKC and the PDZ-domain proteins Bazooka (Baz) and PAR-6. The PAR/aPKC complex is required for the separation of apical and basolateral plasma membrane domains, for the asymmetric localization of cell fate determinants and for the proper orientation of the mitotic spindle. How the complex exerts these different functions is not known. We show that the lipid phosphatase PTEN directly binds to Baz in vitro and in vivo, and colocalizes with Baz in the apical cortex of epithelia and neuroblasts. PTEN is an important regulator of phosphoinositide turnover that antagonizes the activity of PI3-kinase. We show that Pten mutant ovaries and embryos lacking maternal and zygotic Pten function display phenotypes consistent with a function for PTEN in the organization of the actin cytoskeleton. In freshly laid eggs, the germ plasm determinants oskar mRNA and Vasa are not localized properly to the posterior cytocortex and pole cells do not form. In addition, the actin-dependent posterior movement of nuclei during early cleavage divisions does not occur and the synchrony of nuclear divisions at syncytial blastoderm stages is lost. Pten mutant embryos also show severe defects during cellularization. Our data provide evidence for a link between the PAR/aPKC complex, the actin cytoskeleton and PI3-kinase signaling mediated by PTEN.
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Affiliation(s)
- Walter von Stein
- Abteilung Stammzellbiologie, CMPB, Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany
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114
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Abstract
Heterotrimeric G-proteins are intracellular partners of G-protein-coupled receptors (GPCRs). GPCRs act on inactive Galpha.GDP/Gbetagamma heterotrimers to promote GDP release and GTP binding, resulting in liberation of Galpha from Gbetagamma. Galpha.GTP and Gbetagamma target effectors including adenylyl cyclases, phospholipases and ion channels. Signaling is terminated by intrinsic GTPase activity of Galpha and heterotrimer reformation - a cycle accelerated by 'regulators of G-protein signaling' (RGS proteins). Recent studies have identified several unconventional G-protein signaling pathways that diverge from this standard model. Whereas phospholipase C (PLC) beta is activated by Galpha(q) and Gbetagamma, novel PLC isoforms are regulated by both heterotrimeric and Ras-superfamily G-proteins. An Arabidopsis protein has been discovered containing both GPCR and RGS domains within the same protein. Most surprisingly, a receptor-independent Galpha nucleotide cycle that regulates cell division has been delineated in both Caenorhabditis elegans and Drosophila melanogaster. Here, we revisit classical heterotrimeric G-protein signaling and explore these new, non-canonical G-protein signaling pathways.
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Affiliation(s)
- C R McCudden
- Department of Pharmacology, Lineberger Comprehensive Cancer Center, and UNC Neuroscience Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599-7365, USA.
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115
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Abstract
PURPOSE OF REVIEW Theoretic and, in particular, mathematic models can help biologists to select and design experiments, to highlight general principles, to discriminate similar and to link different phenomena, and to predict novel features. Specifically, they contribute to an understanding of latent mechanisms and crucial parameters of biologic processes. The following review gives an overview of recent developments in the field of hematopoietic tissue stem cell modeling. RECENT FINDINGS A number of experimental findings on heterogeneity, flexibility, and plasticity of hematopoietic and other tissue stem cells are challenging the classic stem cell concept of a predefined intrinsic stem cell program. Self-organizing systems provide a more elegant and comprehensive alternative to explain experimental data. SUMMARY Within the last few decades, modeling approaches in stem cell biology have evolved and now encompass a broad spectrum of phenomena, ranging from the cellular level to the tissue level. The application of theoretic models is currently suggesting that we abandon the classic assumption of a strict developmental hierarchy and understand stem cell organization as a dynamic, functional process. Such a perspective has implications for a prospective characterization of tissue stem cells (eg, regarding gene expression profiles and genetic regulation patterns).
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Affiliation(s)
- Markus Loeffler
- Institute for Medical Informatics, Statistics and Epidemiology, University of Leipzig, Germany.
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116
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Abstract
Heterotrimeric G proteins are well known for their function in signal transduction downstream of seven transmembrane receptors. More recently, however, genetic analysis in C. elegans and in Drosophila has revealed a second, essential function of these molecules in positioning the mitotic spindle and attaching microtubules to the cell cortex. Five new publications in Cell (Afshar et al., 2004; Du and Macara, 2004 [this issue of Cell]; Hess et al., 2004), Developmental Cell (Martin-McCaffrey et al., 2004), and Current Biology (Couwenbergs et al., 2004) show that this function is conserved in vertebrates and--like the classical pathway--involves cycling of G proteins between GDP and GTP bound conformations.
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Affiliation(s)
- Bernhard Hampoelz
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Dr Bohr Gasse 3-5, 1030 Vienna, Austria
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117
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Hughes JR, Bullock SL, Ish-Horowicz D. inscuteable mRNA Localization Is Dynein-Dependent and Regulates Apicobasal Polarity and Spindle Length in Drosophila Neuroblasts. Curr Biol 2004; 14:1950-6. [PMID: 15530398 DOI: 10.1016/j.cub.2004.10.022] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2004] [Revised: 09/14/2004] [Accepted: 09/14/2004] [Indexed: 01/10/2023]
Abstract
Drosophila neuroblasts undergo asymmetric divisions along the apicobasal axis to produce two daughter cells of unequal size and different developmental fate. Inscuteable (Insc) protein functions as part of an apically localized complex to coordinate orientation of the mitotic spindle and basal sorting of cell fate determinants. insc mRNA transcripts also localize apically in neuroblasts, yet the mechanism underpinning this process and its developmental significance are unknown. Here, we show that the Egalitarian (Egl)/Bicaudal-D (BicD)/dynein mRNA transport machinery mediates apical localization of insc mRNA transcripts in neuroblasts, and we provide evidence that insc localization is required for efficient apical targeting of Insc protein. egl and BicD mutant neuroblasts display defects in apicobasal polarity, which is consistent with apical Insc activity being reduced. Also, we observe shortened mitotic spindles at metaphase in egl, BicD, and insc mutant neuroblasts and demonstrate a previously unknown, dose-dependent requirement for Insc in augmenting metaphase spindle length. We conclude that localization of insc mRNA transcripts in neuroblasts confers maximal levels of apical Insc activity, which is required for accurate control of metaphase spindle length, division orientation, and asymmetric cell division.
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Affiliation(s)
- Julian R Hughes
- Developmental Genetics Laboratory, Cancer Research UK, Post Office Box 123, 44 Lincoln's Inn Fields, London WC2A 3PX, United Kingdom
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118
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Kriegstein AR, Castañeda-Castellanos DR, Noctor SC. Patterns of cortical neurogenesis. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.cnr.2004.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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119
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Schweisguth F. Formation and remodeling of epithelial polarity. Dev Cell 2004; 6:749-55. [PMID: 15177024 DOI: 10.1016/j.devcel.2004.05.010] [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: 11/21/2022]
Abstract
Polarity is a fundamental property of all eukaryotic cells that underlies many developmental processes. A recent EMBO workshop (March 27-31) organized by Thomas Lecuit, Norbert Perrimon, and Keith Mostov brought cell and developmental biologists together on the Mediterranean coast near Marseille, France, to share views on how epithelium polarity is established and remodeled during development and disease. Participants witnessed and celebrated the emerging convergence of intellectual and experimental approaches to address how individual cells acquire polarity and form polarized tissues in the context of developing embryos.
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Affiliation(s)
- François Schweisguth
- Ecole Normale Supérieure, CNRS UMR 8542, 46 rue d'Ulm, 75230 Paris Cedex 05, France.
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120
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Kosodo Y, Röper K, Haubensak W, Marzesco AM, Corbeil D, Huttner WB. Asymmetric distribution of the apical plasma membrane during neurogenic divisions of mammalian neuroepithelial cells. EMBO J 2004; 23:2314-24. [PMID: 15141162 PMCID: PMC419905 DOI: 10.1038/sj.emboj.7600223] [Citation(s) in RCA: 330] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2003] [Accepted: 04/06/2004] [Indexed: 11/09/2022] Open
Abstract
At the onset of neurogenesis in the mammalian central nervous system, neuroepithelial cells switch from symmetric, proliferative to asymmetric, neurogenic divisions. In analogy to the asymmetric division of Drosophila neuroblasts, this switch of mammalian neuroepithelial cells is thought to involve a change in cleavage plane orientation from perpendicular (vertical cleavage) to parallel (horizontal cleavage) relative to the apical surface of the neuroepithelium. Here, we report, using TIS21-GFP knock-in mouse embryos to identify neurogenic neuroepithelial cells, that at the onset as well as advanced stages of neurogenesis the vast majority of neurogenic divisions, like proliferative divisions, show vertical cleavage planes. Remarkably, however, neurogenic divisions of neuroepithelial cells, but not proliferative ones, involve an asymmetric distribution to the daughter cells of the apical plasma membrane, which constitutes only a minute fraction (1-2%) of the entire neuroepithelial cell plasma membrane. Our results support a novel concept for the cell biological basis of asymmetric, neurogenic divisions of neuroepithelial cells in the mammalian central nervous system.
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Affiliation(s)
- Yoichi Kosodo
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
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121
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Abstract
Asymmetric cell division is a conserved mechanism for partitioning information during mitosis. Over the past several years, significant progress has been made in our understanding of how cells establish polarity during asymmetric cell division and how determinants, in the form of localized proteins and mRNAs, are segregated. In particular, genetic studies in Drosophila and Caenorhabditis elegans have linked cell polarity, G protein signaling and regulation of the cytoskeleton to coordination of mitotic spindle orientation and localization of determinants. Also, several new studies have furthered our understanding of how asymmetrically localized cell fate determinants, such as the Numb, a negative regulator Notch signaling, functions in biasing cell fates in the developing nervous system in Drosophila. In vertebrates, analysis of dividing neural progenitor cells by in vivo imaging has raised questions about the role of asymmetric cell divisions during neurogenesis.
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Affiliation(s)
- Fabrice Roegiers
- Departments of Physiology and Biochemistry, Howard Hughes Medical Institute, University of California, San Francisco, 533 Parnassus Ave, San Francisco, California, 94122, USA
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122
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Haubensak W, Attardo A, Denk W, Huttner WB. Neurons arise in the basal neuroepithelium of the early mammalian telencephalon: a major site of neurogenesis. Proc Natl Acad Sci U S A 2004; 101:3196-201. [PMID: 14963232 PMCID: PMC365766 DOI: 10.1073/pnas.0308600100] [Citation(s) in RCA: 717] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2003] [Indexed: 11/18/2022] Open
Abstract
Neurons of the mammalian CNS are thought to originate from progenitors dividing at the apical surface of the neuroepithelium. Here we use mouse embryos expressing GFP from the Tis21 locus, a gene expressed throughout the neural tube in most, if not all, neuron-generating progenitors, to specifically reveal the cell divisions that produce CNS neurons. In addition to the apical, asymmetric divisions of neuroepithelial (NE) cells that generate another NE cell and a neuron, we find, from the onset of neurogenesis, a second population of progenitors that divide in the basal region of the neuroepithelium and generate two neurons. Basal progenitors are most frequent in the telencephalon, where they outnumber the apically dividing neuron-generating NE cells. Our observations reconcile previous data on the origin and lineage of CNS neurons and show that basal, rather than apical, progenitors are the major source of the neurons of the mammalian neocortex.
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Affiliation(s)
- Wulf Haubensak
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, D-01307 Dresden, Germany
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