Asymmetric Prospero localization is required to generate mixed neuronal/glial lineages in the Drosophila CNS

Development ◽  
2001 ◽  
Vol 128 (20) ◽  
pp. 4103-4112
Author(s):  
Marc R. Freeman ◽  
Chris Q. Doe
Keyword(s):  
Daughter Cell ◽  
Cell Types ◽  
Precursor Cell ◽  
Glial Development ◽  
Daughter Cells ◽  
Cell Divisions ◽  
Common Precursor ◽  
Necessary And Sufficient ◽  
Different Cell Types ◽  
Novel Model

In many organisms, single neural stem cells can generate both neurons and glia. How are these different cell types produced from a common precursor? In Drosophila, glial cells missing (gcm) is necessary and sufficient to induce glial development in the CNS. gcm mRNA has been reported to be asymmetrically localized to daughter cells during precursor cell division, allowing the daughter cell to produce glia while precursor cell generates neurons. We show that (1) gcm mRNA is uniformly distributed during precursor cell divisions; (2) the Prospero transcription factor is asymmetrically localized into the glial-producing daughter cell; (3) Prospero is required to upregulate gcm expression and induce glial development; and (4) mislocalization of Prospero to the precursor cell leads to ectopic gcm expression and the production of extra glia. We propose a novel model for the separation of glia and neuron fates in mixed lineages in which the asymmetric localization of Prospero results in upregulation of gcm expression and initiation of glial development in only precursor daughter cells.

Binary cell death decision regulated by unequal partitioning of Numb at mitosis

Development ◽  
2002 ◽  
Vol 129 (20) ◽  
pp. 4677-4684 ◽  
Author(s):  
Virginie Orgogozo ◽  
François Schweisguth ◽  
Yohanns Bellaïche
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Daughter Cell ◽  
Asymmetric Cell Divisions ◽  
Daughter Cells ◽  
Cell Divisions ◽  
Specific Manner ◽  
Asymmetric Divisions ◽  
Apoptotic Genes ◽  
Necessary And Sufficient

An important issue in Metazoan development is to understand the mechanisms that lead to stereotyped patterns of programmed cell death. In particular, cells programmed to die may arise from asymmetric cell divisions. The mechanisms underlying such binary cell death decisions are unknown. We describe here a Drosophila sensory organ lineage that generates a single multidentritic neuron in the embryo. This lineage involves two asymmetric divisions. Following each division, one of the two daughter cells expresses the pro-apoptotic genes reaper and grim and subsequently dies. The protein Numb appears to be specifically inherited by the daughter cell that does not die. Numb is necessary and sufficient to prevent apoptosis in this lineage. Conversely, activated Notch is sufficient to trigger death in this lineage. These results show that binary cell death decision can be regulated by the unequal segregation of Numb at mitosis. Our study also indicates that regulation of programmed cell death modulates the final pattern of sensory organs in a segment-specific manner.

scholarly journals The MAP She1 coordinates directional spindle positioning by spatially restricting dynein activity

2021 ◽  
Author(s):  
Kari H. Ecklund ◽  
Megan E. Bailey ◽  
Carsten K. Dietvorst ◽  
Charles L. Asbury ◽  
Steven M. Markus
Keyword(s):  
Daughter Cell ◽  
Cell Types ◽  
Division Plane ◽  
Spindle Positioning ◽  
Daughter Cells ◽  
Anaphase Onset ◽  
Microtubule Binding Domain ◽  
Mother And Daughter ◽  
Mother Cells ◽  
Cell Division Plane

ABSTRACTDynein motors move the mitotic spindle to the cell division plane in many cell types, including in budding yeast, in which dynein is assisted by numerous factors including the microtubule-associated protein (MAP) She1. Evidence suggests that She1 plays a role in polarizing dynein-mediated spindle movements toward the daughter cell; however, how She1 performs this function is unknown. We find that She1 assists dynein in maintaining the spindle close to the bud neck, such that at anaphase onset the chromosomes are segregated to mother and daughter cells. She1 does so by attenuating the initiation of dynein-mediated spindle movements specifically within the mother cell, ensuring such movements are polarized toward the daughter cell. Our data indicate that this activity relies on She1 binding to the microtubule-bound conformation of the dynein microtubule-binding domain, and to astral microtubules within mother cells. Our findings reveal how an asymmetrically localized MAP directionally tunes dynein activity by attenuating motor activity in a spatially confined manner.

scholarly journals A high-content RNAi screen reveals multiple roles for long noncoding RNAs in cell division

2019 ◽  
Author(s):  
Lovorka Stojic ◽  
Aaron T L Lun ◽  
Patrice Mascalchi ◽  
Christina Ernst ◽  
Aisling M Redmond ◽  
...  
Keyword(s):  
Cell Division ◽  
Genome Stability ◽  
Noncoding Rnas ◽  
Cell Types ◽  
Long Noncoding Rnas ◽  
Genomic Locus ◽  
Daughter Cells ◽  
Acting Mechanism ◽  
Multiple Cell ◽  
Necessary And Sufficient

ABSTRACTGenome stability relies on proper coordination of mitosis and cytokinesis, where dynamic microtubules capture and faithfully segregate chromosomes into daughter cells. The role of long noncoding RNAs (lncRNAs) in controlling these processes however remains largely unexplored. To identify lncRNAs with mitotic functions, we performed a high-content RNAi imaging screen targeting more than 2,000 human lncRNAs. By investigating major hallmarks of cell division such as chromosome segregation, mitotic duration and cytokinesis, we discovered numerous lncRNAs with functions in each of these processes. The chromatin-associated lncRNA, linc00899, was selected for in-depth studies due to the robust mitotic delay observed upon its depletion. Transcriptome analysis of linc00899-depleted cells together with gain-of-function and rescue experiments across multiple cell types identified the neuronal microtubule-binding protein, TPPP/p25, as a target of linc00899. Linc00899 binds the genomic locus of TPPP/p25 and suppresses its transcription through a cis-acting mechanism. In cells depleted of linc00899, the consequent upregulation of TPPP/p25 alters microtubule dynamics and is necessary and sufficient to delay mitosis. Overall, our comprehensive screen identified several lncRNAs with roles in genome stability and revealed a new lncRNA that controls microtubule behaviour with functional implications beyond cell division.

The Lineages of Neuroglial Cells

1996 ◽  
Vol 2 (6) ◽  
pp. 335-344 ◽  
Author(s):  
Robert P. Skoff
Keyword(s):  
Normal Development ◽  
Cell Types ◽  
Culture Conditions ◽  
Precursor Cell ◽  
Cell Lineages ◽  
Common Precursor ◽  
Normal Environment ◽  
Glial Lineage ◽  
The Brain ◽  
Glial Precursor

The study of neuroglial cell lineages in the CNS identifies the time in development, when astrocytes and oligodendrocytes diverge from a common precursor cell. Recent studies using retroviral tracing show that the lineages for astrocytes and oligodendrocytes begin to diverge as early as embryonic day 13 (E13) in the cerebellum and as early as E15 in the forebrain. A very small percentage of glial precursor cells present in late pre- and postnatal development are pluripotential, but the vast majority of astrocytes and oligodendrocytes in the brain are derived from “committed” precursors. The precursors for these postmitotic astrocytes and oligodendrocytes are immature astrocytes and oligodendrocytes (progenitors) that express molecular properties unique to each of these cell types. It is critical to distinguish glial lineage (thought of in terms of a glial cell's ancestry in normal development) from glial plasticity (the potential of a glial cell to alter its fate when its normal environment is changed). In tissue culture, a bipotential cell known as the O-2A cell generates oligodendrocytes under one set of culture conditions and retains plasticity to become a subtype of astrocyte under another set. Whether all cells phenotyped as O-2A cells in culture are bipotential or whether only a subset displays this capacity is still unclear.

scholarly journals The MAP She1 coordinates directional spindle positioning by spatially restricting dynein activity

2021 ◽  
Author(s):  
Kari H. Ecklund ◽  
Megan E. Bailey ◽  
Kelly A. Kossen ◽  
Carsten K. Dietvorst ◽  
Charles L. Asbury ◽  
...  
Keyword(s):  
Daughter Cell ◽  
Cell Types ◽  
Division Plane ◽  
Spindle Positioning ◽  
Daughter Cells ◽  
Anaphase Onset ◽  
Microtubule Binding Domain ◽  
Close Proximity ◽  
Mother And Daughter ◽  
Mother Cells

Dynein motors move the mitotic spindle to the cell division plane in many cell types, including in budding yeast, in which dynein is assisted by numerous factors including the microtubule-associated protein (MAP) She1. Evidence suggests that She1 plays a role in polarizing dynein-mediated spindle movements toward the daughter cell; however, how She1 performs this function is unknown. We find that She1 assists dynein in maintaining the spindle in close proximity to the bud neck, such that at anaphase onset the chromosomes are segregated to mother and daughter cells. She1 does so by attenuating the initiation of dynein-mediated spindle movements within the mother cell, thus ensuring such movements are polarized toward the daughter cell. Our data indicate that this activity relies on She1 binding to the microtubule-bound conformation of the dynein microtubule-binding domain, and to astral microtubules within mother cells. Our findings reveal how an asymmetrically localized MAP directionally tunes dynein activity by attenuating motor activity in a spatially confined manner.

scholarly journals Diverse mechanisms regulate contractile ring assembly for cytokinesis in the two-cell C. elegans embryo

2022 ◽  
Author(s):  
Imge Ozugergin ◽  
Karina Mastronardi ◽  
Chris Law ◽  
Alisa Piekny
Keyword(s):  
Cell Types ◽  
Somatic Tissue ◽  
Ring Closure ◽  
Contractile Ring ◽  
C Elegans ◽  
Daughter Cells ◽  
The Core ◽  
Ring Assembly ◽  
Different Cell Types ◽  
Ring Position

Cytokinesis occurs at the end of mitosis due to the ingression of a contractile ring that cleaves the daughter cells. The core machinery regulating this crucial process is conserved among metazoans. Multiple pathways control ring assembly, but their contribution in different cell types is not known. We found that in the C. elegans embryo, AB and P1 cells fated to be somatic tissue and germline, respectively, have different cytokinesis kinetics supported by distinct myosin levels and organization. Through perturbation of RhoA or polarity regulators and the generation of tetraploid strains, we found that ring assembly is controlled by multiple fate-dependent factors that include myosin-levels, and mechanisms that respond to cell size. Active Ran coordinates ring position with the segregating chromatids in HeLa cells by forming an inverse gradient with importins that control the cortical recruitment of anillin. We found that the Ran pathway regulates anillin in AB cells, but functions differently in P1 cells. We propose that ring assembly delays in P1 cells caused by low myosin and Ran signaling coordinate the timing of ring closure with their somatic neighbours.

scholarly journals The Ran pathway uniquely regulates cytokinesis in cells with different fates in the early C. elegans embryo

2021 ◽  
Author(s):  
Imge Ozugergin ◽  
Karina Mastronardi ◽  
Chris Law ◽  
Alisa Piekny
Keyword(s):  
Cell Fate ◽  
Cell Types ◽  
Contractile Ring ◽  
C Elegans ◽  
Multiple Parameters ◽  
Daughter Cells ◽  
The Core ◽  
Cortical Patterning ◽  
Different Cell Types ◽  
In Cells

ABSTRACTCytokinesis occurs at the end of mitosis and occurs due to the ingression of a contractile ring that cleaves the daughter cells. This process is tightly controlled to prevent cell fate changes or aneuploidy, and the core machinery is highly conserved among metazoans. Multiple mechanisms regulate cytokinesis, but their requirement in different cell types is not known. Here, we show that differently fated AB and P1 cells in the early C. elegans embryo have unique cytokinesis kinetics supported by distinct levels and cortical patterning of myosin. Through perturbation of polarity regulators and the generation of stable tetraploid strains, we demonstrate that these differences depend on both cell fate and size. Additionally, these parameters could influence the Ran pathway, which coordinates the contractile ring with chromatin position, and controls cytokinesis differently in AB and P1 cells. Our findings demonstrate the need to consider multiple parameters when modeling ring kinetics.

Stimulated Virus Production in Vinblastine and Cytochalasin-Induced Multinucleate Cells

1970 ◽  
Vol 28 ◽  
pp. 186-187
Author(s):  
Krishan Awtar
Keyword(s):  
Cell Division ◽  
Normal Cell ◽  
Virus Production ◽  
Multinucleate Cells ◽  
Daughter Cells ◽  
Cell Divisions ◽  
Nuclear Membranes ◽  
Division 2 ◽  
Vinblastine Sulfate

Exposure of cells to low sublethal but mitosis-arresting doses of vinblastine sulfate (Velban) results in the initial arrest of cells in mitosis followed by their subsequent return to an “interphase“-like stage. A large number of these cells reform their nuclear membranes and form large multimicronucleated cells, some containing as many as 25 or more micronuclei (1). Formation of large multinucleate cells is also caused by cytochalasin, by causing the fusion of daughter cells at the end of an otherwise .normal cell division (2). By the repetition of this process through subsequent cell divisions, large cells with 6 or more nuclei are formed.

Study of the Molecular Architecture of Keratin Filaments by Electron Microscopy

1982 ◽  
Vol 40 ◽  
pp. 118-119
Author(s):  
U. Aebi ◽  
P. Rew ◽  
T.-T. Sun
Keyword(s):  
Electron Microscopy ◽  
Structural Organization ◽  
Cell Types ◽  
Structural Features ◽  
Molecular Architecture ◽  
The Past ◽  
Keratin Filaments ◽  
Different Types ◽  
10 Nm Filaments ◽  
Different Cell Types

Various types of intermediate-sized (10-nm) filaments have been found and described in many different cell types during the past few years. Despite the differences in the chemical composition among the different types of filaments, they all yield common structural features: they are usually up to several microns long and have a diameter of 7 to 10 nm; there is evidence that they are made of several 2 to 3.5 nm wide protofilaments which are helically wound around each other; the secondary structure of the polypeptides constituting the filaments is rich in ∞-helix. However a detailed description of their structural organization is lacking to date.

Processing and Characterization of Recombinant von Willebrand Factor Expressed in Different Cell Types Using a Vaccinia Virus Vector

1992 ◽  
Vol 67 (01) ◽  
pp. 154-160 ◽  
Author(s):  
P Meulien ◽  
M Nishino ◽  
C Mazurier ◽  
K Dott ◽  
G Piétu ◽  
...  
Keyword(s):  
Vaccinia Virus ◽  
Von Willebrand Factor ◽  
Human Fibroblasts ◽  
Active Form ◽  
Cell Types ◽  
Biologically Active ◽  
L Cells ◽  
Von Willebrand ◽  
Different Cell Types ◽  
Willebrand Factor

SummaryThe cloning of the cDNA encoding von Willebrand factor (vWF) has revealed that it is synthesized as a large precursor (pre-pro-vWF) molecule and it is now clear that the prosequence or vWAgll is responsible for the intracellular multimerization of vWF. We have cloned the complete vWF cDNA and expressed it using a recombinant vaccinia virus as vector. We have characterized the structure and function of the recombinant vWF (rvWF) secreted from five different cell types: baby hamster kidney (BHK), Chinese hamster ovary (CHO), human fibroblasts (143B), mouse fibroblasts (L) and primary embryonic chicken cells. Forty-eight hours after infection, the quantity of vWF antigen found in the cell supernatant varied from 3 to 12 U/dl depending on the cell type. By SDS-agarose gel electrophoresis, the percentage of high molecular weight forms of vWF varied from 39 to 49% relative to normal plasma for BHK, CHO, 143B and chicken cells but was less than 10% for L cells. In all cell types, the two anodic subbands of each multimer were missing. The two cathodic subbands were easily detected only in BHK and L cells. By SDS-PAGE of reduced samples, pro-vWF was present in similar quantity to the fully processed vWF subunit in L cells, present in moderate amounts in BHK and CHO and in very low amounts in 143B and chicken cells. rvWF from all cells bound to collagen and to platelets in the presence of ristocetin, the latter showing a high correlation between binding efficiency and degree of multimerization. rvWF from all cells was also shown to bind to purified FVIII and in this case binding appeared to be independent of the degree of multimerization. We conclude that whereas vWF is naturally synthesized only by endothelial cells and megakaryocytes, it can be expressed in a biologically active form from various other cell types.

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