scholarly journals A microtubule-based mechanism predicts cell division orientation in plant embryogenesis

2018 ◽  
Author(s):  
Bandan Chakrabortty ◽  
Viola Willemsen ◽  
Thijs de Zeeuw ◽  
Che-Yang Liao ◽  
Dolf Weijers ◽  
...  
Keyword(s):  
Cell Division ◽  
Cell Walls ◽  
Cell Shape ◽  
Cortical Microtubule ◽  
Minimal Set ◽  
Division Plane ◽  
Plant Morphogenesis ◽  
Cell Divisions ◽  
Microtubule Stability ◽  
Underlying Mechanisms

AbstractOriented cell divisions are significant in plant morphogenesis because plant cells are embedded in cell walls and cannot relocate. Cell divisions follow various regular orientations, but the underlying mechanisms have not been clarified. We show that cell-shape dependent self-organisation of cortical microtubule arrays is crucial for determining planes of early tissue-generating divisions and forms the basis for robust control of cell division orientation in the embryo. To achieve this, we simulate microtubules on actual cell surface shapes from which we derive a minimal set of three rules for proper array orientation. The first rule captures the effects of cell shape alone on microtubule organisation, the second rule describes the regulation of microtubule stability at cell edges and the third rule includes the differential effect of auxin on local microtubule stability. These rules explain early embryonic division plane orientations and offer a framework for understanding patterned cell divisions in plant morphogenesis.

scholarly journals Apical Constriction Reversal upon Mitotic Entry Underlies Different Morphogenetic Outcomes of Cell Division

2019 ◽  
Author(s):  
Clint S. Ko ◽  
Prateek Kalakuntla ◽  
Adam C. Martin
Keyword(s):  
Cell Division ◽  
Cell Shape ◽  
Mitotic Cell ◽  
Signal Interference ◽  
Apical Constriction ◽  
Mitotic Entry ◽  
Cell Divisions ◽  
Cell Shape Changes ◽  
Shape Changes ◽  
Mitotic Cells

AbstractDuring development, coordinated cell shape changes and cell divisions sculpt tissues. While these individual cell behaviors have been extensively studied, how cell shape changes and cell divisions that occur concurrently in epithelia influence tissue shape is less understood. We addressed this question in two contexts of the early Drosophila embryo: premature cell division during mesoderm invagination, and native ectodermal cell divisions with ectopic activation of apical contractility. Using quantitative live-cell imaging, we demonstrated that mitotic entry reverses apical contractility by interfering with medioapical RhoA signaling. While premature mitotic entry inhibits mesoderm invagination, which relies on apical constriction, mitotic entry in an artificially contractile ectoderm induced ectopic tissue invaginations. Ectopic invaginations resulted from medioapical myosin loss in neighboring mitotic cells. This myosin loss enabled non-mitotic cells to apically constrict through mitotic cell stretching. Thus, the spatial pattern of mitotic entry can differentially regulate tissue shape through signal interference between apical contractility and mitosis.

scholarly journals Cells tile a flat plane by controlling geometries during morphogenesis of Pyropia thalli

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3314 ◽  
Author(s):  
Kai Xu ◽  
Yan Xu ◽  
Dehua Ji ◽  
Ting Chen ◽  
Changsheng Chen ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Division ◽  
Light Microscope ◽  
Cell Walls ◽  
Single Layer ◽  
Two Dimensional ◽  
Regular Polygons ◽  
Cell Divisions ◽  
Stages Of Growth ◽  
Perfect Model

Background Pyropia haitanensis thalli, which are made of a single layer of polygonal cells, are a perfect model for studying the morphogenesis of multi-celled organisms because their cell proliferation process is an excellent example of the manner in which cells control their geometry to create a two-dimensional plane. Methods Cellular geometries of thalli at different stages of growth revealed by light microscope analysis. Results This study showed the cell division transect the middle of the selected paired-sides to divide the cell into two equal portions, thus resulting in cell sides ≥4 and keeping the average number of cell sides at approximately six even as the thallus continued to grow, such that more than 90% of the cells in thalli longer than 0.08 cm had 5–7 sides. However, cell division could not fully explain the distributions of intracellular angles. Results showed that cell-division-associated fast reorientation of cell sides and cell divisions together caused 60% of the inner angles of cells from longer thalli to range from 100–140°. These results indicate that cells prefer to form regular polygons. Conclusions This study suggests that appropriate cell-packing geometries maintained by cell division and reorientation of cell walls can keep the cells bordering each other closely, without gaps.

scholarly journals Plant cell divisions: variations from the shortest symmetric path

2020 ◽  
Vol 48 (6) ◽  
pp. 2743-2752
Author(s):  
Léo Serra ◽  
Sarah Robinson
Keyword(s):  
Cell Division ◽  
Cell Polarity ◽  
Plant Cell ◽  
Cell Walls ◽  
Direct Consequence ◽  
Spatial Arrangement ◽  
Subcellular Structure ◽  
Cell Divisions ◽  
Developmental Contexts ◽  
Hormonal Signalling

In plants, the spatial arrangement of cells within tissues and organs is a direct consequence of the positioning of the new cell walls during cell division. Since the nineteenth century, scientists have proposed rules to explain the orientation of plant cell divisions. Most of these rules predict the new wall will follow the shortest path passing through the cell centroid halving the cell into two equal volumes. However, in some developmental contexts, divisions deviate significantly from this rule. In these situations, mechanical stress, hormonal signalling, or cell polarity have been described to influence the division path. Here we discuss the mechanism and subcellular structure required to define the cell division placement then we provide an overview of the situations where division deviates from the shortest symmetric path.

scholarly journals The interaction between the tumour suppressor Dlg1 and the MAGUK protein CASK is required for oriented cell division in mammalian epithelia

2018 ◽  
Author(s):  
Andrew P. Porter ◽  
Gavin White ◽  
Natalie A. Mack ◽  
Angeliki Malliri
Keyword(s):  
Cell Division ◽  
Epithelial Cells ◽  
3D Culture ◽  
Direct Interaction ◽  
Tumour Suppressor ◽  
Spindle Orientation ◽  
Oriented Cell Division ◽  
Cell Divisions ◽  
Microtubule Stability ◽  
Maguk Protein

AbstractOriented cell divisions are important for the formation of normal epithelial structures. Dlg1, a tumour suppressor, is required for oriented cell division in Drosophila epithelia and chick neuroepithelia, but how Dlg1 is localised to the membrane and its importance in mammalian epithelia are unknown. Here we show that Dlg1 is required in non-transformed mammalian epithelial cells for oriented cell divisions, and for normal lumen formation in 3D culture. We demonstrate that CASK, a membrane-associated scaffold, is the factor responsible for Dlg1 membrane localisation during spindle orientation, and thereby identify a new cellular function for CASK. We show that depletion of CASK leads to misoriented divisions in 3D, and to the formation of multilumen structures in cultured kidney and breast epithelial cells. Blocking the direct interaction between CASK and Dlg1 with an interfering peptide disrupts spindle orientation and causes multilumen formation. We further show that the Dlg1-CASK interaction is important for the membrane localisation of the canonical LGN-NuMA complex, required for attachment of the mitotic spindle to the membrane and its correct positioning, as well as for astral microtubule stability. Together these results establish the importance of the CASK-Dlg1 interaction in oriented cell division and epithelial integrity.

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.

scholarly journals Inhibition of cell expansion enhances cortical microtubule stability in the root apex of Arabidopsis thaliana

2021 ◽  
Vol 28 (1) ◽  
Author(s):  
Veronica Giourieva ◽  
Emmanuel Panteris
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Cell Expansion ◽  
Cortical Microtubule ◽  
Root Apex ◽  
Cellulose Synthase ◽  
Cellulose Biosynthesis ◽  
Cortical Microtubules ◽  
Wild Type ◽  
Microtubule Stability

Abstract Background Cortical microtubules regulate cell expansion by determining cellulose microfibril orientation in the root apex of Arabidopsis thaliana. While the regulation of cell wall properties by cortical microtubules is well studied, the data on the influence of cell wall to cortical microtubule organization and stability remain scarce. Studies on cellulose biosynthesis mutants revealed that cortical microtubules depend on Cellulose Synthase A (CESA) function and/or cell expansion. Furthermore, it has been reported that cortical microtubules in cellulose-deficient mutants are hypersensitive to oryzalin. In this work, the persistence of cortical microtubules against anti-microtubule treatment was thoroughly studied in the roots of several cesa mutants, namely thanatos, mre1, any1, prc1-1 and rsw1, and the Cellulose Synthase Interacting 1 protein (csi1) mutant pom2-4. In addition, various treatments with drugs affecting cell expansion were performed on wild-type roots. Whole mount tubulin immunolabeling was applied in the above roots and observations were performed by confocal microscopy. Results Cortical microtubules in all mutants showed statistically significant increased persistence against anti-microtubule drugs, compared to those of the wild-type. Furthermore, to examine if the enhanced stability of cortical microtubules was due to reduced cellulose biosynthesis or to suppression of cell expansion, treatments of wild-type roots with 2,6-dichlorobenzonitrile (DCB) and Congo red were performed. After these treatments, cortical microtubules appeared more resistant to oryzalin, than in the control. Conclusions According to these findings, it may be concluded that inhibition of cell expansion, irrespective of the cause, results in increased microtubule stability in A. thaliana root. In addition, cell expansion does not only rely on cortical microtubule orientation but also plays a regulatory role in microtubule dynamics, as well. Various hypotheses may explain the increased cortical microtubule stability under decreased cell expansion such as the role of cell wall sensors and the presence of less dynamic cortical microtubules.

scholarly journals SepF is the FtsZ anchor in archaea, with features of an ancestral cell division system

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nika Pende ◽  
Adrià Sogues ◽  
Daniela Megrian ◽  
Anna Sartori-Rupp ◽  
Patrick England ◽  
...  
Keyword(s):  
Cell Division ◽  
Common Ancestor ◽  
Phylogenetic Analyses ◽  
Super Resolution ◽  
Binding Mode ◽  
Last Universal Common Ancestor ◽  
Division Plane ◽  
Multiple Factors ◽  
Universal Common Ancestor ◽  
Super Resolution Microscopy

AbstractMost archaea divide by binary fission using an FtsZ-based system similar to that of bacteria, but they lack many of the divisome components described in model bacterial organisms. Notably, among the multiple factors that tether FtsZ to the membrane during bacterial cell constriction, archaea only possess SepF-like homologs. Here, we combine structural, cellular, and evolutionary analyses to demonstrate that SepF is the FtsZ anchor in the human-associated archaeon Methanobrevibacter smithii. 3D super-resolution microscopy and quantitative analysis of immunolabeled cells show that SepF transiently co-localizes with FtsZ at the septum and possibly primes the future division plane. M. smithii SepF binds to membranes and to FtsZ, inducing filament bundling. High-resolution crystal structures of archaeal SepF alone and in complex with the FtsZ C-terminal domain (FtsZCTD) reveal that SepF forms a dimer with a homodimerization interface driving a binding mode that is different from that previously reported in bacteria. Phylogenetic analyses of SepF and FtsZ from bacteria and archaea indicate that the two proteins may date back to the Last Universal Common Ancestor (LUCA), and we speculate that the archaeal mode of SepF/FtsZ interaction might reflect an ancestral feature. Our results provide insights into the mechanisms of archaeal cell division and pave the way for a better understanding of the processes underlying the divide between the two prokaryotic domains.

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