scholarly journals Organelle segregation during mitosis: Lessons from asymmetrically dividing cells

2012 ◽  
Vol 196 (3) ◽  
pp. 305-313 ◽  
Author(s):  
Jimmy Ouellet ◽  
Yves Barral
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Division ◽  
Cell Fate ◽  
Chromosome Segregation ◽  
Cellular Aging ◽  
P Granules ◽  
Organelle Segregation ◽  
Organelle Distribution ◽  
Dividing Cells

Studies on cell division traditionally focus on the mechanisms of chromosome segregation and cytokinesis, yet we know comparatively little about how organelles segregate. Analysis of organelle partitioning in asymmetrically dividing cells has provided insights into the mechanisms through which cells control organelle distribution. Interestingly, these studies have revealed that segregation mechanisms frequently link organelle distribution to organelle growth and formation. Furthermore, in many cases, cells use organelles, such as the endoplasmic reticulum and P granules, as vectors for the segregation of information. Together, these emerging data suggest that the coordination between organelle growth, division, and segregation plays an important role in the control of cell fate inheritance, cellular aging, and rejuvenation, i.e., the resetting of age in immortal lineages.

scholarly journals The endoplasmic reticulum is partitioned asymmetrically during mitosis before cell fate selection in proneuronal cells in the early Drosophila embryo

2017 ◽  
Vol 28 (11) ◽  
pp. 1530-1538 ◽  
Author(s):  
Anthony S. Eritano ◽  
Arturo Altamirano ◽  
Sarah Beyeler ◽  
Norma Gaytan ◽  
Mark Velasquez ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Division ◽  
Cell Fate ◽  
Asymmetric Cell Division ◽  
Asymmetric Division ◽  
Drosophila Embryo ◽  
Early Drosophila Embryo ◽  
Dividing Cells ◽  
Fate Determinants ◽  
Selection Of

Asymmetric cell division is the primary mechanism to generate cellular diversity, and it relies on the correct partitioning of cell fate determinants. However, the mechanism by which these determinants are delivered and positioned is poorly understood, and the upstream signal to initiate asymmetric cell division is unknown. Here we report that the endoplasmic reticulum (ER) is asymmetrically partitioned during mitosis in epithelial cells just before delamination and selection of a proneural cell fate in the early Drosophila embryo. At the start of gastrulation, the ER divides asymmetrically into a population of asynchronously dividing cells at the anterior end of the embryo. We found that this asymmetric division of the ER depends on the highly conserved ER membrane protein Jagunal (Jagn). RNA inhibition of jagn just before the start of gastrulation disrupts this asymmetric division of the ER. In addition, jagn-deficient embryos display defects in apical-basal spindle orientation in delaminated embryonic neuroblasts. Our results describe a model in which an organelle is partitioned asymmetrically in an otherwise symmetrically dividing cell population just upstream of cell fate determination and updates previous models of spindle-based selection of cell fate during mitosis.

fumble Encodes a Pantothenate Kinase Homolog Required for Proper Mitosis and Meiosis in Drosophila melanogaster

Genetics ◽  
2001 ◽  
Vol 157 (3) ◽  
pp. 1267-1276
Author(s):  
Katayoun Afshar ◽  
Pierre Gönczy ◽  
Stephen DiNardo ◽  
Steven A Wasserman
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Cell Division Cycle ◽  
Protein Isoforms ◽  
Pantothenate Kinase ◽  
Male Germline ◽  
Dividing Cells ◽  
Mutant Cells ◽  
Mitosis And Meiosis

Abstract A number of fundamental processes comprise the cell division cycle, including spindle formation, chromosome segregation, and cytokinesis. Our current understanding of these processes has benefited from the isolation and analysis of mutants, with the meiotic divisions in the male germline of Drosophila being particularly well suited to the identification of the required genes. We show here that the fumble (fbl) gene is required for cell division in Drosophila. We find that dividing cells in fbl-deficient testes exhibit abnormalities in bipolar spindle organization, chromosome segregation, and contractile ring formation. Cytological analysis of larval neuroblasts from null mutants reveals a reduced mitotic index and the presence of polyploid cells. Molecular analysis demonstrates that fbl encodes three protein isoforms, all of which contain a domain with high similarity to the pantothenate kinases of A. nidulans and mouse. The largest Fumble isoform is dispersed in the cytoplasm during interphase, concentrates around the spindle at metaphase, and localizes to the spindle midbody at telophase. During early embryonic development, the protein localizes to areas of membrane deposition and/or rearrangement, such as the metaphase and cellularization furrows. Given the role of pantothenate kinase in production of Coenzyme A and in phospholipid biosynthesis, this pattern of localization is suggestive of a role for fbl in membrane synthesis. We propose that abnormalities in synthesis and redistribution of membranous structures during the cell division cycle underlie the cell division defects in fbl mutant cells.

scholarly journals Regulation of store-operated calcium entry during cell division

2012 ◽  
Vol 40 (1) ◽  
pp. 119-123 ◽  
Author(s):  
Jeremy T. Smyth ◽  
James W. Putney
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Division ◽  
Recent Work ◽  
Calcium Entry ◽  
Store Operated Calcium Entry ◽  
Dividing Cells ◽  
Complex Mechanisms ◽  
Molecular Components ◽  
Ca2 Channels

Store-operate Ca2+ channels gate Ca2+ entry into the cytoplasm in response to the depletion of Ca2+ from endoplasmic reticulum Ca2+ stores. The major molecular components of store-operated Ca2+ entry are STIM (stromal-interacting molecule) 1 (and in some instances STIM2) that serves as the endoplasmic reticulum Ca2+ sensor, and Orai (Orai1, Orai2 and Orai3) which function as pore-forming subunits of the store-operated channel. It has been known for some time that store-operated Ca2+ entry is shut down during cell division. Recent work has revealed complex mechanisms regulating the functions and locations of both STIM1 and Orai1 in dividing cells.

scholarly journals The nature of cell division forces in epithelial monolayers

2021 ◽  
Vol 220 (8) ◽  
Author(s):  
Vivek K. Gupta ◽  
Sungmin Nam ◽  
Donghyun Yim ◽  
Jaclyn Camuglia ◽  
Judy Lisette Martin ◽  
...  
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Morphological Changes ◽  
Tissue Growth ◽  
Force Generation ◽  
Model Organisms ◽  
Epithelial Monolayers ◽  
Dividing Cells ◽  
Division Axis ◽  
Universal Mechanism

Epithelial cells undergo striking morphological changes during division to ensure proper segregation of genetic and cytoplasmic materials. These morphological changes occur despite dividing cells being mechanically restricted by neighboring cells, indicating the need for extracellular force generation. Beyond driving cell division itself, forces associated with division have been implicated in tissue-scale processes, including development, tissue growth, migration, and epidermal stratification. While forces generated by mitotic rounding are well understood, forces generated after rounding remain unknown. Here, we identify two distinct stages of division force generation that follow rounding: (1) Protrusive forces along the division axis that drive division elongation, and (2) outward forces that facilitate postdivision spreading. Cytokinetic ring contraction of the dividing cell, but not activity of neighboring cells, generates extracellular forces that propel division elongation and contribute to chromosome segregation. Forces from division elongation are observed in epithelia across many model organisms. Thus, division elongation forces represent a universal mechanism that powers cell division in confining epithelia.

scholarly journals Regulation of Membrane Localization of Sanpodo by lethal giant larvae and neuralized in Asymmetrically Dividing Cells of Drosophila Sensory Organs

2005 ◽  
Vol 16 (8) ◽  
pp. 3480-3487 ◽  
Author(s):  
Fabrice Roegiers ◽  
Lily Yeh Jan ◽  
Yuh Nung Jan
Keyword(s):  
Cell Division ◽  
Notch Signaling ◽  
Cell Fate ◽  
Asymmetric Cell Division ◽  
Transmembrane Protein ◽  
Negative Regulator ◽  
Membrane Localization ◽  
Lethal Giant Larvae ◽  
Dividing Cells ◽  
Fate Decision

In Drosophila, asymmetric division occurs during proliferation of neural precursors of the central and peripheral nervous system (PNS), where a membrane-associated protein, Numb, is asymmetrically localized during cell division and is segregated to one of the two daughter cells (the pIIb cell) after mitosis. numb has been shown genetically to function as an antagonist of Notch signaling and also as a negative regulator of the membrane localization of Sanpodo, a four-pass transmembrane protein required for Notch signaling during asymmetric cell division in the CNS. Previously, we identified lethal giant larvae (lgl) as a gene required for numb-mediated inhibition of Notch in the adult PNS. In this study we show that Sanpodo is expressed in asymmetrically dividing precursor cells of the PNS and that Sanpodo internalization in the pIIb cell is dependent cytoskeletally associated Lgl. Lgl specifically regulates internalization of Sanpodo, likely through endocytosis, but is not required for the endocytosis Delta, which is a required step in the Notch-mediated cell fate decision during asymmetric cell division. Conversely, the E3 ubiquitin ligase neuralized is required for both Delta endocytosis and the internalization of Sanpodo. This study identifies a hitherto unreported role for Lgl as a regulator of Sanpodo during asymmetric cell division in the adult PNS.

scholarly journals Ultrastructure and Differentiation in Chara Sp. II. Mitosis

1967 ◽  
Vol 20 (5) ◽  
pp. 883 ◽  
Author(s):  
JD Pickett-Heaps
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Division ◽  
Asymmetric Cell Division ◽  
Metaphase Plate ◽  
Early Prophase ◽  
Cell Organelles ◽  
Vegetative Cells ◽  
Nucleolar Material ◽  
Dividing Cells ◽  
Late Telophase

The ultrastructure of some dividing cells of Chara are described. No centrioles have ever been detected in vegetative cells. Asymmetric cell division, forming a predetermined pattern of cells, was apparently not preceded by any characteristic grouping of cell organelles. The nucleoli became dispersed during pre-prophase, and most of the nucleolar material appeared intimately associated with the chromosomes throughout division, although some seemed excluded from the nucleus at late telophase. Polar zones of endoplasmic reticulum were formed in early prophase, and attachment of microtubules to daughter chromosomes slightly preceded the formation of a very precisely aligned metaphase plate. The chromosome arms were also apparently all aligned in the plane of this plate.

scholarly journals Centromere function in asymmetric cell division in Drosophila female and male germline stem cells

Open Biology ◽  
2021 ◽  
Vol 11 (11) ◽  
Author(s):  
Antje M. Kochendoerfer ◽  
Federica Modafferi ◽  
Elaine M. Dunleavy
Keyword(s):  
Stem Cells ◽  
Cell Division ◽  
Cell Fate ◽  
Chromosome Segregation ◽  
Asymmetric Cell Division ◽  
Genetic Material ◽  
Asymmetric Distribution ◽  
Germline Stem Cells ◽  
Male Germline ◽  
Male Germline Stem Cells

The centromere is the constricted chromosomal region required for the correct separation of the genetic material at cell division. The kinetochore protein complex assembles at the centromere and captures microtubules emanating from the centrosome to orchestrate chromosome segregation in mitosis and meiosis. Asymmetric cell division (ACD) is a special type of mitosis that generates two daughter cells with different fates. Epigenetic mechanisms operating at the centromere have been proposed to contribute to ACD. Recent studies have shown that an asymmetric distribution of CENP-A—the centromere-specific histone H3 variant—between sister chromatids can bias chromosome segregation in ACD. In stem cells, this leads to non-random sister chromatid segregation, which can affect cell fate. These findings support the ‘silent sister' hypothesis, according to which the mechanisms of ACD are epigenetically regulated through centromeres. Here, we review the recent data implicating centromeres in ACDs and cell fate in Drosophila melanogaster female and male germline stem cells.

scholarly journals Asymmetric centrosome behavior and the mechanisms of stem cell division

2008 ◽  
Vol 180 (2) ◽  
pp. 261-266 ◽  
Author(s):  
Yukiko M. Yamashita ◽  
Margaret T. Fuller
Keyword(s):  
Cell Division ◽  
Cell Fate ◽  
Spindle Orientation ◽  
Germline Stem Cells ◽  
Cell Fate Decisions ◽  
Male Germline ◽  
Dividing Cells ◽  
A Cell ◽  
Direct Cell ◽  
Fate Determinants

The ability of dividing cells to produce daughters with different fates is an important developmental mechanism conserved from bacteria to fungi, plants, and metazoan animals. Asymmetric outcomes of a cell division can be specified by two general mechanisms: asymmetric segregation of intrinsic fate determinants or asymmetric placement of daughter cells into microenvironments that provide extrinsic signals that direct cells to different states. For both, spindle orientation must be coordinated with the localization of intrinsic determinants or source of extrinsic signals to achieve the proper asymmetric outcome. Recent work on spindle orientation in Drosophila melanogaster male germline stem cells and neuroblasts has brought into sharp focus the key role of differential centrosome behavior in developmentally programmed asymmetric division (for reviews see Cabernard, C., and C.Q. Doe. 2007. Curr. Biol. 17:R465–R467; Gonzalez, C. 2007. Nat. Rev. Genet. 8:462–472). These findings provide new insights and suggest intriguing new models for how cells coordinate spindle orientation with their cellular microenvironment to regulate and direct cell fate decisions within tissues.

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

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

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

scholarly journals Crosstalk between endoplasmic reticulum stress and oxidative stress: a dynamic duo in multiple myeloma

2021 ◽  
Author(s):  
Sinan Xiong ◽  
Wee-Joo Chng ◽  
Jianbiao Zhou
Keyword(s):  
Oxidative Stress ◽  
Multiple Myeloma ◽  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Cell Fate ◽  
Stress Responses ◽  
Plasma Cells ◽  
Reactive Oxygen Species Generation ◽  
Future Research ◽  
And Oxidative Stress

AbstractUnder physiological and pathological conditions, cells activate the unfolded protein response (UPR) to deal with the accumulation of unfolded or misfolded proteins in the endoplasmic reticulum. Multiple myeloma (MM) is a hematological malignancy arising from immunoglobulin-secreting plasma cells. MM cells are subject to continual ER stress and highly dependent on the UPR signaling activation due to overproduction of paraproteins. Mounting evidence suggests the close linkage between ER stress and oxidative stress, demonstrated by overlapping signaling pathways and inter-organelle communication pivotal to cell fate decision. Imbalance of intracellular homeostasis can lead to deranged control of cellular functions and engage apoptosis due to mutual activation between ER stress and reactive oxygen species generation through a self-perpetuating cycle. Here, we present accumulating evidence showing the interactive roles of redox homeostasis and proteostasis in MM pathogenesis and drug resistance, which would be helpful in elucidating the still underdefined molecular pathways linking ER stress and oxidative stress in MM. Lastly, we highlight future research directions in the development of anti-myeloma therapy, focusing particularly on targeting redox signaling and ER stress responses.

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