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 Phosphoinositide signaling plays a key role in cytokinesis

2006 ◽  
Vol 174 (4) ◽  
pp. 485-490 ◽  
Author(s):  
Chris Janetopoulos ◽  
Peter Devreotes
Keyword(s):  
Cell Division ◽  
Cell Polarity ◽  
Cell Morphology ◽  
Cell Shape ◽  
Phosphoinositide Signaling ◽  
Complex Series ◽  
Vital Functions ◽  
Cell Shape Changes ◽  
Shape Changes

To perform the vital functions of motility and division, cells must undergo dramatic shifts in cell polarity. Recent evidence suggests that polarized distributions of phosphatidylinositol 4,5-bisphosphate and phosphatidylinositol 3,4,5-trisphosphate, which are clearly important for regulating cell morphology during migration, also play an important role during the final event in cell division, which is cytokinesis. Thus, there is a critical interplay between the membrane phosphoinositides and the cytoskeletal cortex that regulates the complex series of cell shape changes that accompany these two processes.

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

2020 ◽  
Vol 31 (16) ◽  
pp. 1663-1674 ◽  
Author(s):  
Clint S. Ko ◽  
Prateek Kalakuntla ◽  
Adam C. Martin
Keyword(s):  
Cell Division ◽  
Tissue Level ◽  
Spatiotemporal Patterns ◽  
Force Generation ◽  
Tissue Morphogenesis ◽  
Apical Constriction ◽  
Mitotic Entry ◽  
Cell Divisions

Cell divisions can either promote or inhibit tissue morphogenesis. In contractile epithelia, mitotic entry disrupts medioapical myosin activation and reverses apical constriction. We found that different spatiotemporal patterns of mitotic entry and the resultant changes in force generation at the tissue level dictate distinct tissue shape outcomes.

scholarly journals Hyperactivation of the folded gastrulation pathway induces specific cell shape changes

Development ◽  
1998 ◽  
Vol 125 (4) ◽  
pp. 589-597 ◽  
Author(s):  
P. Morize ◽  
A.E. Christiansen ◽  
M. Costa ◽  
S. Parks ◽  
E. Wieschaus
Keyword(s):  
Cell Shape ◽  
Inducible Promoter ◽  
Specific Cell ◽  
Apical Surface ◽  
Apical Constriction ◽  
Cellular Effects ◽  
Ventral Furrow ◽  
Cell Shape Changes ◽  
Shape Changes

During Drosophila gastrulation, mesodermal precursors are brought into the interior of the embryo by formation of the ventral furrow. The first steps of ventral furrow formation involve a flattening of the apical surface of the presumptive mesodermal cells and a constriction of their apical diameters. In embryos mutant for folded gastrulation (fog), these cell shape changes occur but the timing and synchrony of the constrictions are abnormal. A similar phenotype is seen in a maternal effect mutant, concertina (cta). fog encodes a putative secreted protein whereas cta encodes an (alpha)-subunit of a heterotrimeric G protein. We have proposed that localized expression of the fog signaling protein induces apical constriction by interacting with a receptor whose downstream cellular effects are mediated by the cta G(alpha)protein. <P> In order to test this model, we have ectopically expressed fog at the blastoderm stage using an inducible promoter. In addition, we have examined the constitutive activation of cta protein by blocking GTP hydrolysis using both in vitro synthesized mutant alleles and cholera toxin treatment. Activation of the fog/cta pathway by any of these procedures results in ectopic cell shape changes in the gastrula. Uniform fog expression rescues the gastrulation defects of fog null embryos but not cta mutant embryos, arguing that cta functions downstream of fog expression. The normal location of the ventral furrow in embryos with uniformly expressed fog suggests the existence of a fog-independent pathway determining mesoderm-specific cell behaviors and invagination. Epistasis experiments indicate that this pathway requires snail but not twist expression.

Real-time imaging of cell-cell adherens junctions reveals that Drosophila mesoderm invagination begins with two phases of apical constriction of cells

2001 ◽  
Vol 114 (3) ◽  
pp. 493-501 ◽  
Author(s):  
H. Oda ◽  
S. Tsukita
Keyword(s):  
Real Time ◽  
Cell Shape ◽  
Adherens Junctions ◽  
Cell Sheet ◽  
Apical Surface ◽  
Apical Constriction ◽  
Real Time Imaging ◽  
Cell Shape Changes ◽  
Shape Changes ◽  
Cell Cell

Invagination of the epithelial cell sheet of the prospective mesoderm in Drosophila gastrulation is a well-studied, relatively simple morphogenetic event that results from dynamic cell shape changes and cell movements. However, these cell behaviors have not been followed at a sufficiently short time resolution. We examined mesoderm invagination in living wild-type embryos by real-time imaging of fluorescently labeled cell-cell adherens junctions, which are located at the apical zones of cell-cell contact. Low-light fluorescence video microscopy directly visualized the onset and progression of invagination. In an initial period of approximately 2 minutes, cells around the ventral midline reduced their apical surface areas slowly in a rather synchronous manner. Next, the central and more lateral cells stochastically accelerated or initiated their apical constriction, giving rise to random arrangements of cells with small and relatively large apices. Thus, we found that mesoderm invagination began with slow synchronous and subsequent fast stochastic phases of cell apex constriction. Furthermore, we showed that the mesoderm invagination of folded gastrulation mutant embryos lacked the normal two constriction phases, and instead began with asynchronous, feeble cell shape changes. Our observations suggested that Folded gastrulation-mediated signaling enabled synchronous activation of the contractile cortex, causing competition among the individual mesodermal cells for apical constriction. Movies available on-line: http://www.biologists.com/JCS/movies/jcs2073.html

scholarly journals Orchestrating morphogenesis: building the body plan by cell shape changes and movements

Development ◽  
2020 ◽  
Vol 147 (17) ◽  
pp. dev191049 ◽  
Author(s):  
Kia Z. Perez-Vale ◽  
Mark Peifer
Keyword(s):  
Cell Shape ◽  
Molecular Mechanisms ◽  
Fruit Fly ◽  
Body Plan ◽  
The Body ◽  
Collective Cell Migration ◽  
Convergent Extension ◽  
Apical Constriction ◽  
Cell Shape Changes ◽  
Shape Changes

ABSTRACTDuring embryonic development, a simple ball of cells re-shapes itself into the elaborate body plan of an animal. This requires dramatic cell shape changes and cell movements, powered by the contractile force generated by actin and myosin linked to the plasma membrane at cell-cell and cell-matrix junctions. Here, we review three morphogenetic events common to most animals: apical constriction, convergent extension and collective cell migration. Using the fruit fly Drosophila as an example, we discuss recent work that has revealed exciting new insights into the molecular mechanisms that allow cells to change shape and move without tearing tissues apart. We also point out parallel events at work in other animals, which suggest that the mechanisms underlying these morphogenetic processes are conserved.

scholarly journals Microtubules enter centre stage for morphogenesis

2020 ◽  
Vol 375 (1809) ◽  
pp. 20190557 ◽  
Author(s):  
Katja Röper
Keyword(s):  
Cell Division ◽  
Cell Shape ◽  
Dynamic Networks ◽  
Tissue Level ◽  
Epithelial Morphogenesis ◽  
Direct Role ◽  
Cell Shape Changes ◽  
Epithelial Sheets ◽  
Cytoskeletal System ◽  
Shape Changes

Cell shape changes are key to observable changes at the tissue level during morphogenesis and organ formation. The major driver of cell shape changes in turn is the actin cytoskeleton, both in the form of protrusive linear or branched dynamic networks and in the form of contractile actomyosin. Over the last 20 years, actomyosin has emerged as the major cytoskeletal system that deforms cells in epithelial sheets during morphogenesis. By contrast, the second major cytoskeletal system, microtubules, have so far mostly been assumed to serve ‘house-keeping' functions, such as directed transport or cell division, during morphogenetic events. Here, I will reflect on a subset of studies over the last 10 years that have clearly shown a major direct role for the microtubule cytoskeleton in epithelial morphogenesis, suggesting that our focus will need to be widened to give more attention and credit to this cytoskeletal system in playing an active morphogenetic role. This article is part of a discussion meeting issue ‘Contemporary morphogenesis'.

scholarly journals Mechano-chemical feedback leads to competition for BMP signalling during pattern formation

2020 ◽  
Author(s):  
Daniel Toddie-Moore ◽  
Martti Montanari ◽  
Ngan Vi Tran ◽  
Evgeniy Brik ◽  
Hanna Antson ◽  
...  
Keyword(s):  
Cell Fate ◽  
Cell Shape ◽  
Active Form ◽  
Type I ◽  
Apical Constriction ◽  
Pupal Wing ◽  
Cell Shape Changes ◽  
Bmp Signalling ◽  
Cellular Behaviour ◽  
Shape Changes

Developmental patterning is thought to be regulated by conserved signalling pathways. Initial patterns are often broad before refining to only those cells that commit to a particular fate. However, the mechanisms by which pattern refinement takes place remain to be addressed. Using the posterior crossvein (PCV) of the Drosophila pupal wing as a model, into which bone morphogenetic protein (BMP) ligand is extracellularly transported to instruct vein patterning, we investigate how pattern refinement is regulated. We found that BMP signalling induces apical enrichment of Myosin II in developing crossvein cells to regulate apical constriction. Live imaging of cellular behaviour indicates that changes in cell shape are dynamic and transient, only being maintained in those cells that retain vein fate after refinement. Disrupting cell shape changes throughout the PCV inhibits pattern refinement. In contrast, disrupting cell shape in only a subset of vein cells can result in a loss of BMP signalling. In addition, we observed that expressing the constitutively active form of the BMP type I receptor in clones caused apical constriction autonomously and often induced BMP signalling loss in the PCV region in a non-autonomous manner. We propose that the cell shape changes of future PCV cells allow them to compete more efficiently for the basally localised BMP signal by forming a mechano-chemical feedback loop. This study highlights a new form of competition among the cells: competing for a signal that induces cell fate.

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