scholarly journals Actomyosin-driven tension at compartmental boundaries orients cell division independently of cell geometry in vivo

2018 ◽  
Author(s):  
Elena Scarpa ◽  
Cédric Finet ◽  
Guy Blanchard ◽  
Bénédicte Sanson
Keyword(s):  
Cell Division ◽  
Laser Ablation ◽  
Spindle Pole ◽  
Cell Geometry ◽  
Cable Tension ◽  
Animal Development ◽  
Axis Extension ◽  
Necessary And Sufficient ◽  
Actomyosin Cytoskeleton

AbstractDuring animal development, planar polarization of the actomyosin cytoskeleton underlies key morphogenetic events such as axis extension and boundary formation. Actomyosin is enriched along compartment boundaries during segmentation of the Drosophila embryo, forming supracellular contractile cables that keep cells segregated at boundaries. Here, we show that these contractile actomyosin cables bias the orientation of division in cells in contact with compartment boundaries. By decreasing actomyosin cable tension locally using laser ablation or, conversely ectopically increasing tension using laser wounding, we demonstrate that localised subcellular force is necessary and sufficient to orient mitoses in vivo. Moreover this bias is independent of cell geometry and involves capture of the spindle pole by the actomyosin cortex.

scholarly journals MICROTUBULE BIOGENESIS AND CELL SHAPE IN OCHROMONAS

1973 ◽  
Vol 56 (2) ◽  
pp. 340-359 ◽  
Author(s):  
G. Benjamin Bouck ◽  
David L. Brown
Keyword(s):  
Cell Division ◽  
Cell Shape ◽  
Spindle Pole ◽  
Vegetative Cells ◽  
External Wall ◽  
Cell Form ◽  
Attachment Sites ◽  
Spindle Microtubules ◽  
Mitotic Cells

In the first of two companion papers which attempt to correlate microtubules and their nucleating sites with developmental and cell division patterns in the unicellular flagellate, Ochromonas, the distribution of cytoplasmic and mitotic microtubules and various kinetosome-related fibers are detailed. Of the five kinetosome-related fibers, which have been found in Ochromonas, two, the kineto-beak fibers and the rhizoplast fibers are utilized as attachment sites for distinct groups of microtubules. The set of microtubules attached to the kineto-beak fibers apparently shape the anterior beak region of the cell whereas the rhizoplast microtubules appear to extend into and shape the tail in vegetative cells. In mitotic cells a rhizoplast is found at each spindle pole apparently serving as foci for the spindle microtubules. These findings are discussed in relation to the less well defined attachment sites for vegetative and mitotic microtubules in other kinds of cells. It is noted that the effects of depolymerizing microtubules in vivo might be easily quantitated in whole populations since no external wall or pellicle contributes to the maintenance or the biogenesis of the characteristic cell form of Ochromonas.

scholarly journals Actomyosin-Driven Tension at Compartmental Boundaries Orients Cell Division Independently of Cell Geometry In Vivo

2018 ◽  
Vol 47 (6) ◽  
pp. 727-740.e6 ◽  
Author(s):  
Elena Scarpa ◽  
Cédric Finet ◽  
Guy B. Blanchard ◽  
Bénédicte Sanson
Keyword(s):  
Cell Division ◽  
Cell Geometry

scholarly journals Identification of circRNA circ-CSPP1 as a potent driver of colorectal cancer by directly targeting the miR-431/LASP1 axis

2021 ◽  
Vol 16 (1) ◽  
pp. 523-536
Author(s):  
Minghao Li ◽  
Jianbin Zhuang ◽  
Di Kang ◽  
Yuzhuo Chen ◽  
Weiliang Song
Keyword(s):  
Colorectal Cancer ◽  
Cancer Biology ◽  
Spindle Pole ◽  
Circular Rnas ◽  
Cell Progression ◽  
Crc Management ◽  
Common Malignancy

Abstract Colorectal cancer (CRC) is the third most common malignancy worldwide. Circular RNAs (circRNAs) have been implicated in cancer biology. The purpose of the current work is to investigate the precise parts of circRNA centrosome and spindle pole-associated protein 1 (circ-CSPP1) in the progression of CRC. Our data showed that circ-CSPP1 was significantly overexpressed in CRC tissues and cells. The knockdown of circ-CSPP1 attenuated cell proliferation, migration, invasion and promoted apoptosis in vitro and weakened tumor growth in vivo. circ-CSPP1 directly targeted miR-431, and circ-CSPP1 knockdown modulated CRC cell progression in vitro via upregulating miR-431. Moreover, LIM and SH3 protein 1 (LASP1) was a functional target of miR-431 in modulating CRC cell malignant progression. Furthermore, circ-CSPP1 in CRC cells functioned as a posttranscriptional regulator on LASP1 expression by targeting miR-431. Our present study identified the oncogenic role of circ-CSPP1 in CRC partially by the modulation of the miR-431/LASP1 axis, providing evidence for circ-CSPP1 as a promising biomarker for CRC management.

scholarly journals NK cell activation through the NKG2D ligand MULT-1 is selectively prevented by the glycoprotein encoded by mouse cytomegalovirus gene m145

2005 ◽  
Vol 201 (2) ◽  
pp. 211-220 ◽  
Author(s):  
Astrid Krmpotic ◽  
Milena Hasan ◽  
Andrea Loewendorf ◽  
Tanja Saulig ◽  
Anne Halenius ◽  
...  
Keyword(s):  
Cell Activation ◽  
Nk Cell ◽  
Surface Expression ◽  
Viral Gene ◽  
Nkg2d Ligand ◽  
Mouse Cytomegalovirus ◽  
Mcmv Infection ◽  
Viral Survival ◽  
Necessary And Sufficient

The NK cell–activating receptor NKG2D interacts with three different cellular ligands, all of which are regulated by mouse cytomegalovirus (MCMV). We set out to define the viral gene product regulating murine UL16-binding protein-like transcript (MULT)-1, a newly described NKG2D ligand. We show that MCMV infection strongly induces MULT-1 gene expression, but surface expression of this glycoprotein is nevertheless completely abolished by the virus. Screening a panel of MCMV deletion mutants defined the gene m145 as the viral regulator of MULT-1. The MCMV m145-encoded glycoprotein turned out to be necessary and sufficient to regulate MULT-1 by preventing plasma membrane residence of MULT-1. The importance of MULT-1 in NK cell regulation in vivo was confirmed by the attenuating effect of the m145 deletion that was lifted after NK cell depletion. Our findings underline the significance of escaping MULT-1/NKG2D signaling for viral survival and maintenance.

scholarly journals Paired arrangement of kinetochores together with microtubule pivoting and dynamics drive kinetochore capture in meiosis I

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Gheorghe Cojoc ◽  
Ana-Maria Florescu ◽  
Alexander Krull ◽  
Anna H. Klemm ◽  
Nenad Pavin ◽  
...  
Keyword(s):  
Cell Division ◽  
Fission Yeast ◽  
General Feature ◽  
Protein Complexes ◽  
Spindle Pole ◽  
Single Object ◽  
Homologous Chromosomes ◽  
Angular Movement ◽  
Spindle Microtubules ◽  
Meiosis I

Abstract Kinetochores are protein complexes on the chromosomes, whose function as linkers between spindle microtubules and chromosomes is crucial for proper cell division. The mechanisms that facilitate kinetochore capture by microtubules are still unclear. In the present study, we combine experiments and theory to explore the mechanisms of kinetochore capture at the onset of meiosis I in fission yeast. We show that kinetochores on homologous chromosomes move together, microtubules are dynamic and pivot around the spindle pole, and the average capture time is 3–4 minutes. Our theory describes paired kinetochores on homologous chromosomes as a single object, as well as angular movement of microtubules and their dynamics. For the experimentally measured parameters, the model reproduces the measured capture kinetics and shows that the paired configuration of kinetochores accelerates capture, whereas microtubule pivoting and dynamics have a smaller contribution. Kinetochore pairing may be a general feature that increases capture efficiency in meiotic cells.

scholarly journals The nucleoporin Nup205/NPP-3 is lost near centrosomes at mitotic onset and can modulate the timing of this process in Caenorhabditis elegans embryos

2012 ◽  
Vol 23 (16) ◽  
pp. 3111-3121 ◽  
Author(s):  
Virginie Hachet ◽  
Coralie Busso ◽  
Mika Toya ◽  
Asako Sugimoto ◽  
Peter Askjaer ◽  
...  
Keyword(s):  
Cell Division ◽  
Rna Interference ◽  
Caenorhabditis Elegans ◽  
Nuclear Envelope ◽  
Aurora A Kinase ◽  
Aurora A ◽  
Time And Space ◽  
Local Loss ◽  
Necessary And Sufficient

Regulation of mitosis in time and space is critical for proper cell division. We conducted an RNA interference–based modifier screen to identify novel regulators of mitosis in Caenorhabditis elegans embryos. Of particular interest, this screen revealed that the Nup205 nucleoporin NPP-3 can negatively modulate the timing of mitotic onset. Furthermore, we discovered that NPP-3 and nucleoporins that are associated with it are lost from the nuclear envelope (NE) in the vicinity of centrosomes at the onset of mitosis. We demonstrate that centrosomes are both necessary and sufficient for NPP-3 local loss, which also requires the activity of the Aurora-A kinase AIR-1. Our findings taken together support a model in which centrosomes and AIR-1 promote timely onset of mitosis by locally removing NPP-3 and associated nucleoporins from the NE.

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