scholarly journals Degenerating Drosophila Larval Epidermal Cells Drive Thorax Closure

2020 ◽  
Author(s):  
Thamarailingam Athilingam ◽  
Saurabh Singh Parihar ◽  
Rachita Bhattacharya ◽  
Mohd. Suhail Rizvi ◽  
Amit Kumar ◽  
...  

AbstractAdult thorax formation in Drosophila begins during pre-pupal development by fusion of its two contralateral progenitor halves, the heminotal epithelia (HE). HEs migrate and replace an underlying cell layer of thoracic larval epidermal cells (LECs) during a morphogenetic process called thorax closure. The LEC layer has so far been proposed to be a passive substrate over which HEs migrate before their zipping. By contrast, here we show that the pull forces generated within the LEC layer drive HE migration. During thorax closure, the LECs display actomyosin-mediated contraction, via enrichment of non-muscle myosin-II and actin, besides squamous-to-pseudostratified columnar epithelial transition and tissue shrinkage. This shrinkage of the LEC layer is further accompanied by cell extrusion and death, that prevent overcrowding of LECs, thereby promoting further shrinkage. The pull forces thus generated by the shrinking LEC layer are then relayed to the HEs by their mutual adhesions via βPS1 (Mys) and αPS3 (Scb) integrins. Suppression of cell death in the LEC layer by a gain of p35 leads to cell overcrowding, which impedes HE migration and zipping. Further, knockdown of sqh, the light chain of non-muscle myosin II, in LECs or integrins (mys or scb) in either the LEC layer or in the HEs, or both abrogate thorax closure. Mathematical modeling also reveals the biophysical underpinnings of the forces that drive this tissue closure process wherein a degenerating LEC layer mediates its succession by the future adult primodia. These essential principles of thorax closure appear ancient in origin and recur in multiple morphogenetic contexts and tissue repair.

Haematologica ◽  
2018 ◽  
Vol 103 (12) ◽  
pp. 1997-2007 ◽  
Author(s):  
Pedro L. Moura ◽  
Bethan R. Hawley ◽  
Tosti J. Mankelow ◽  
Rebecca E. Griffiths ◽  
Johannes G.G. Dobbe ◽  
...  

2017 ◽  
Vol 13 (7) ◽  
pp. 384-384
Author(s):  
Katharine H. Wrighton

2015 ◽  
Vol 43 (12) ◽  
pp. 3025-3039 ◽  
Author(s):  
O. Moreno-Arotzena ◽  
C. Borau ◽  
N. Movilla ◽  
M. Vicente-Manzanares ◽  
J. M. García-Aznar

Development ◽  
1996 ◽  
Vol 122 (11) ◽  
pp. 3433-3441 ◽  
Author(s):  
M.C. Perbal ◽  
G. Haughn ◽  
H. Saedler ◽  
Z. Schwarz-Sommer

In Antirrhinum majus, petal and stamen organ identity is controlled by two MADS-box transcription factors, DEFICIENS and GLOBOSA. Mutations in either of these genes result in the replacement of petals by sepaloid organs and stamens by carpelloid organs. Somatically stable def and glo periclinal chimeras, generated by transposon excision events, were used to study the non-cell-autonomous functions of these two MADS-box proteins. Two morphologically distinct types of chimeras were analysed using genetic, morphological and molecular techniques. Restoration of DEF expression in the L1 cell layer results in the reestablishment of DEF and GLO functions in L1-derived cells only; inner layer cells retain their mutant sepaloid features. Nevertheless, this activity is sufficient to allow the expansion of petal lobes, highlighting the role of DEF in the stimulation of cell proliferation and/or cell shape and elongation when expressed in the L1 layer. Establishment of DEF or GLO expression in L2 and L3 cell layers is accompanied by the recovery of petaloid identity of the epidermal cells but it is insufficient to allow petal lobe expansion. We show by in situ immunolocalisation that the non-cell-autonomy is due to direct trafficking of DEF and GLO proteins from the inner layer to the epidermal cells. At least for DEF, this movement appears to be polar since DEF acts cell-autonomously when expressed in the L1 cell layer. Furthermore, the petaloid revertant sectors observed on second whorl mutant organs and the mutant margins of petals of L2L3 chimeras suggest that DEF and GLO intradermal movement is limited. This restriction may reflect the difference in the regulation of primary plasmodesmata connecting cells from the same layer and secondary plasmodesmata connecting cells from different layers. We propose that control of intradermal trafficking of DEF and GLO could play a role in maintaining of the boundaries of their expression domains.


Physiology ◽  
2002 ◽  
Vol 17 (5) ◽  
pp. 213-218 ◽  
Author(s):  
Caspar Rüegg ◽  
Claudia Veigel ◽  
Justin E. Molloy ◽  
Stephan Schmitz ◽  
John C. Sparrow ◽  
...  

Muscle myosin II is an ATP-driven, actin-based molecular motor. Recent developments in optical tweezers technology have made it possible to study movement and force production on the single-molecule level and to find out how different myosin isoforms may have adapted to their specific physiological roles.


2021 ◽  
Author(s):  
Anja Schmidt ◽  
Long Li ◽  
Zhiyi Lv ◽  
Shuling Yan ◽  
Jörg Großhans

Rho signaling with its major targets the formin Dia, Rho kinase (Rok) and non-muscle myosin II control turnover, amount and contractility of actomyosin. Much less investigated has been a potential function for the distribution of F-actin plus and minus ends. In syncytial Drosophila embryos Rho1 signaling is high between actin caps, i. e. the cortical intercap region. Capping protein binds to free plus ends of F-actin to prevent elongation of the filament. Capping protein has served as a marker to visualize the distribution of F-actin plus ends in cells and in vitro. Here, we probed the distribution of plus ends with capping protein in syncytial Drosophila embryos. We found that Capping proteins are specifically enriched in the intercap region similar to Dia and MyoII but distinct from overall F-actin. The intercap enrichment of Capping protein was impaired in dia mutants and embryos, in which Rok and MyoII activation was inhibited. Our observations reveal that Dia and Rok/MyoII control Capping protein enrichment and support a model that Dia and Rok/MyoII control the organization of cortical actin cytoskeleton downstream of Rho1 signaling.


2021 ◽  
Author(s):  
Hanqing Guo ◽  
Michael Swan ◽  
Shicheng Huang ◽  
Bing He

Apical constriction driven by non-muscle myosin II (″myosin″) provides a well-conserved mechanism to mediate epithelial folding. It remains unclear how contractile forces near the apical surface of a cell sheet drive out-of-plane bending of the sheet and whether myosin contractility is required throughout folding. By optogenetic-mediated acute inhibition of myosin, we find that during Drosophila mesoderm invagination, myosin contractility is critical to prevent tissue relaxation during the early, ″priming″ stage of folding but is dispensable for the actual folding step after the tissue passes through a stereotyped transitional configuration, suggesting that the mesoderm is mechanically bistable during gastrulation. Combining computer modeling and experimental measurements, we show that the observed mechanical bistability arises from an in-plane compression from the surrounding ectoderm, which promotes mesoderm invagination by facilitating a buckling transition. Our results indicate that Drosophila mesoderm invagination requires a joint action of local apical constriction and global in-plane compression to trigger epithelial buckling.


Cell Reports ◽  
2018 ◽  
Vol 24 (4) ◽  
pp. 1060-1070.e4 ◽  
Author(s):  
Michele L. Markwardt ◽  
Nicole E. Snell ◽  
Min Guo ◽  
Yicong Wu ◽  
Ryan Christensen ◽  
...  

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1458 ◽  
Author(s):  
Gloria Asensio-Juárez ◽  
Clara Llorente-González ◽  
Miguel Vicente-Manzanares

The MYH9 gene encodes the heavy chain (MHCII) of non-muscle myosin II A (NMII-A). This is an actin-binding molecular motor essential for development that participates in many crucial cellular processes such as adhesion, cell migration, cytokinesis and polarization, maintenance of cell shape and signal transduction. Several types of mutations in the MYH9 gene cause an array of autosomal dominant disorders, globally known as MYH9-related diseases (MYH9-RD). These include May-Hegglin anomaly (MHA), Epstein syndrome (EPS), Fechtner syndrome (FTS) and Sebastian platelet syndrome (SPS). Although caused by different MYH9 mutations, all patients present macrothrombocytopenia, but may later display other pathologies, including loss of hearing, renal failure and presenile cataracts. The correlation between the molecular and cellular effects of the different mutations and clinical presentation are beginning to be established. In this review, we correlate the defects that MYH9 mutations cause at a molecular and cellular level (for example, deficient filament formation, altered ATPase activity or actin-binding) with the clinical presentation of the syndromes in human patients. We address why these syndromes are tissue restricted, and the existence of possible compensatory mechanisms, including residual activity of mutant NMII-A and/or the formation of heteropolymers or co-polymers with other NMII isoforms.


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