scholarly journals Ends and middle: global force balance determines septum location in fission yeast

2019 ◽  
Author(s):  
Xavier Le Goff ◽  
Jordi Comelles ◽  
Charles Kervrann ◽  
Daniel Riveline
Keyword(s):  
Cell Division ◽  
Fission Yeast ◽  
Asymmetric Cell Division ◽  
Quantitative Imaging ◽  
Force Balance ◽  
Radius Of Curvature ◽  
Division Plane ◽  
Division Site ◽  
Global Force ◽  
Scaling Arguments

AbstractThe fission yeast cell is shaped as a very regular cylinder ending by hemi-spheres at both cell ends. Its conserved phenotypes are often used as read-outs for classifying interacting genes and protein networks. Using Pascal and Young-Laplace laws, we proposed a framework where scaling arguments predicted shapes. Here we probed quantitatively one of these relations which predicts that the division site would be located closer to the cell end with the larger radius of curvature. By combining genetics and quantitative imaging, we tested experimentally whether altered shapes of cell end correlate with a displaced division site, leading to asymmetric cell division. Our results show that the division site position depends on the radii of curvatures of both ends. This new geometrical mechanism for the proper division plane positioning could be essential to achieve even partitioning of cellular material at each cell division.

Asymmetric cell division in fucoid algae: a role for cortical adhesions in alignment of the mitotic apparatus

2001 ◽  
Vol 114 (23) ◽  
pp. 4319-4328
Author(s):  
Sherryl R. Bisgrove ◽  
Darryl L. Kropf
Keyword(s):  
Cell Division ◽  
Asymmetric Cell Division ◽  
Cell Cortex ◽  
Mitotic Apparatus ◽  
Pharmacological Agents ◽  
Division Plane ◽  
Adhesion Sites ◽  
Spindle Poles ◽  
Pelvetia Compressa ◽  
Two Phases

The first cell division in zygotes of the fucoid brown alga Pelvetia compressa is asymmetric and we are interested in the mechanism controlling the alignment of this division. Since the division plane bisects the mitotic apparatus, we investigated the timing and mechanism of spindle alignments. Centrosomes, which give rise to spindle poles, aligned with the growth axis in two phases – a premetaphase rotation of the nucleus and centrosomes followed by a postmetaphase alignment that coincided with the separation of the mitotic spindle poles during anaphase and telophase. The roles of the cytoskeleton and cell cortex in the two phases of alignment were analyzed by treatment with pharmacological agents. Treatments that disrupted cytoskeleton or perturbed cortical adhesions inhibited pre-metaphase alignment and we propose that this rotational alignment is effected by microtubules anchored at cortical adhesion sites. Postmetaphase alignment was not affected by any of the treatments tested, and may be dependent on asymmetric cell morphology.

scholarly journals Asymmetric cell division: Plane but not simple

2001 ◽  
Vol 11 (6) ◽  
pp. R233-R236 ◽  
Author(s):  
Paul N. Adler ◽  
Job Taylor
Keyword(s):  
Cell Division ◽  
Asymmetric Cell Division ◽  
Division Plane ◽  
Cell Division Plane

Microtubule Architectural Dynamics Determine Cell Shape and Cell Division Site in Fission Yeast

2004 ◽  
Vol 10 (S02) ◽  
pp. 162-163
Author(s):  
Isabelle Loiodice ◽  
Marcel E. Janson ◽  
Jamye Staub ◽  
Thanuja Gangi-Setty ◽  
Nam P. Nguyen ◽  
...  
Keyword(s):  
Cell Division ◽  
Fission Yeast ◽  
Cell Shape ◽  
Division Site

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.

scholarly journals Roles of putative Rho-GEF Gef2 in division-site positioning and contractile-ring function in fission yeast cytokinesis

2012 ◽  
Vol 23 (7) ◽  
pp. 1181-1195 ◽  
Author(s):  
Yanfang Ye ◽  
I-Ju Lee ◽  
Kurt W. Runge ◽  
Jian-Qiu Wu
Keyword(s):  
Fission Yeast ◽  
Rho Gtpases ◽  
Nucleotide Exchange ◽  
Contractile Ring ◽  
Division Plane ◽  
Cell Functions ◽  
Division Site ◽  
Ring Assembly ◽  
And Function ◽  
Rho Gef

Cytokinesis is crucial for integrating genome inheritance and cell functions. In multicellular organisms, Rho-guanine nucleotide exchange factors (GEFs) and Rho GTPases are key regulators of division-plane specification and contractile-ring formation during cytokinesis, but how they regulate early steps of cytokinesis in fission yeast remains largely unknown. Here we show that putative Rho-GEF Gef2 and Polo kinase Plo1 coordinate to control the medial cortical localization and function of anillin-related protein Mid1. The division-site positioning defects of gef2∆ plo1-ts18 double mutant can be partially rescued by increasing Mid1 levels. We find that Gef2 physically interacts with the Mid1 N-terminus and modulates Mid1 cortical binding. Gef2 localization to cortical nodes and the contractile ring depends on its last 145 residues, and the DBL-homology domain is important for its function in cytokinesis. Our data suggest the interaction between Rho-GEFs and anillins is an important step in the signaling pathways during cytokinesis. In addition, Gef2 also regulates contractile-ring function late in cytokinesis and may negatively regulate the septation initiation network. Collectively, we propose that Gef2 facilitates and stabilizes Mid1 binding to the medial cortex, where the localized Mid1 specifies the division site and induces contractile-ring assembly.

scholarly journals Cytoplasmic MTOCs control spindle orientation for asymmetric cell division in plants

2017 ◽  
Vol 114 (42) ◽  
pp. E8847-E8854 ◽  
Author(s):  
Ken Kosetsu ◽  
Takashi Murata ◽  
Moé Yamada ◽  
Momoko Nishina ◽  
Joanna Boruc ◽  
...  
Keyword(s):  
Cell Division ◽  
Asymmetric Cell Division ◽  
Physcomitrella Patens ◽  
De Novo ◽  
Critical Role ◽  
Fine Tuning ◽  
Spindle Orientation ◽  
Mitotic Apparatus ◽  
Division Plane ◽  
Division Axis

Proper orientation of the cell division axis is critical for asymmetric cell divisions that underpin cell differentiation. In animals, centrosomes are the dominant microtubule organizing centers (MTOC) and play a pivotal role in axis determination by orienting the mitotic spindle. In land plants that lack centrosomes, a critical role of a microtubular ring structure, the preprophase band (PPB), has been observed in this process; the PPB is required for orienting (before prophase) and guiding (in telophase) the mitotic apparatus. However, plants must possess additional mechanisms to control the division axis, as certain cell types or mutants do not form PPBs. Here, using live imaging of the gametophore of the moss Physcomitrella patens, we identified acentrosomal MTOCs, which we termed “gametosomes,” appearing de novo and transiently in the prophase cytoplasm independent of PPB formation. We show that gametosomes are dispensable for spindle formation but required for metaphase spindle orientation. In some cells, gametosomes appeared reminiscent of the bipolar MT “polar cap” structure that forms transiently around the prophase nucleus in angiosperms. Specific disruption of the polar caps in tobacco cells misoriented the metaphase spindles and frequently altered the final division plane, indicating that they are functionally analogous to the gametosomes. These results suggest a broad use of transient MTOC structures as the spindle orientation machinery in plants, compensating for the evolutionary loss of centrosomes, to secure the initial orientation of the spindle in a spatial window that allows subsequent fine-tuning of the division plane axis by the guidance machinery.

scholarly journals Cell cortex microtubules contribute to division plane positioning during telophase in maize

2021 ◽  
Author(s):  
Marschal A. Bellinger ◽  
Aimee N. Uyehara ◽  
Pablo Martinez ◽  
Michael C. McCarthy ◽  
Carolyn G. Rasmussen
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Cell Cortex ◽  
Cell Wall Formation ◽  
Division Plane ◽  
Specific Location ◽  
Division Site ◽  
Plant Cell Division ◽  
Defective Mutant ◽  
Transient Interactions

AbstractThe phragmoplast is a plant-specific microtubule and microfilament structure that forms during telophase to direct new cell wall formation. The phragmoplast expands towards a specific location at the cell cortex called the division site. How the phragmoplast accurately reaches the division site is currently unknown. We show that a previously uncharacterized microtubule arrays accumulated at the cell cortex. These microtubules were organized by transient interactions with division-site localized proteins and were then incorporated into the phragmoplast to guide it towards the division site. A phragmoplast-guidance defective mutant, tangled1, had aberrant cortical-telophase microtubule accumulation that correlated with phragmoplast positioning defects. Division-site localized proteins may promote proper division plane positioning by organizing the cortical-telophase microtubule array to guide the phragmoplast to the division site during plant cell division.One Sentence SummaryMicrotubules accumulate at the cell cortex and interact with the plant division machinery to direct its movement towards the division site.

scholarly journals Chromosome segregation drives division site selection inStreptococcus pneumoniae

2016 ◽  
Author(s):  
Renske van Raaphorst ◽  
Morten Kjos ◽  
Jan-Willem Veening
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Site Selection ◽  
Bacterial Cell Division ◽  
Division Plane ◽  
Canonical Systems ◽  
Daughter Cells ◽  
Division Site ◽  
Additional Protein ◽  
Site Control

AbstractAccurate spatial and temporal positioning of the tubulin-like protein FtsZ is key for proper bacterial cell division.Streptococcus pneumoniae(pneumococcus) is an oval-shaped, symmetrically dividing human pathogen lacking the canonical systems for division site control (nucleoid occlusion and the Min-system). Recently, the early division protein MapZ was identified and implicated in pneumococcal division site selection. We show that MapZ is important for proper division plane selection; thus the question remains what drives pneumococcal division site selection. By mapping the cell cycle in detail, we show that directly after replication both chromosomal origin regions localize to the future cell division sites, prior to FtsZ. Perturbing the longitudinal chromosomal organization by mutating the condensin SMC, by CRISPR/Cas9-mediated chromosome cutting or by poisoning DNA decatenation resulted in mistiming of MapZ and FtsZ positioning and subsequent cell elongation. Together, we demonstrate an intimate relationship between DNA replication, chromosome segregation and division site selection in the pneumococcus, providing a simple way to ensure equally sized daughter cells without the necessity for additional protein factors.

scholarly journals The Cell-End Factor Pom1p Inhibits Mid1p in Specification of the Cell Division Plane in Fission Yeast

2006 ◽  
Vol 16 (24) ◽  
pp. 2480-2487 ◽  
Author(s):  
Neal N. Padte ◽  
Sophie G. Martin ◽  
Martin Howard ◽  
Fred Chang
Keyword(s):  
Cell Division ◽  
Fission Yeast ◽  
Division Plane ◽  
Cell Division Plane
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