scholarly journals Increased lateral tension is sufficient for epithelial folding in Drosophila

Development ◽  
2020 ◽  
Vol 147 (23) ◽  
pp. dev194316
Author(s):  
Liyuan Sui ◽  
Christian Dahmann
Keyword(s):  
Apical Cell ◽  
Wing Disc ◽  
Mechanical Force ◽  
Force Generation ◽  
Mechanical Tension ◽  
Lateral Tension ◽  
Disc Cells ◽  
Tension Increase ◽  
Fold Formation ◽  
Epithelial Sheets

ABSTRACTThe folding of epithelial sheets is important for tissues, organs and embryos to attain their proper shapes. Epithelial folding requires subcellular modulations of mechanical forces in cells. Fold formation has mainly been attributed to mechanical force generation at apical cell sides, but several studies indicate a role of mechanical tension at lateral cell sides in this process. However, whether lateral tension increase is sufficient to drive epithelial folding remains unclear. Here, we have used optogenetics to locally increase mechanical force generation at apical, lateral or basal sides of epithelial Drosophila wing disc cells, an important model for studying morphogenesis. We show that optogenetic recruitment of RhoGEF2 to apical, lateral or basal cell sides leads to local accumulation of F-actin and increase in mechanical tension. Increased lateral tension, but not increased apical or basal tension, results in sizeable fold formation. Our results stress the diversification of folding mechanisms between different tissues and highlight the importance of lateral tension increase for epithelial folding.

scholarly journals Drosophila FGF cleavage is required for efficient intracellular sorting and intercellular dispersal

2019 ◽  
Vol 218 (5) ◽  
pp. 1653-1669 ◽  
Author(s):  
Alex Sohr ◽  
Lijuan Du ◽  
Ruofan Wang ◽  
Li Lin ◽  
Sougata Roy
Keyword(s):  
Drosophila Melanogaster ◽  
Feedback Control ◽  
Wing Disc ◽  
Enzymatic Cleavage ◽  
Basal Surface ◽  
Apical Side ◽  
Intracellular Mechanism ◽  
Disc Cells ◽  
Intracellular Sorting ◽  
Signaling Activity

How morphogenetic signals are prepared for intercellular dispersal and signaling is fundamental to the understanding of tissue morphogenesis. We discovered an intracellular mechanism that prepares Drosophila melanogaster FGF Branchless (Bnl) for cytoneme-mediated intercellular dispersal during the development of the larval Air-Sac-Primordium (ASP). Wing-disc cells express Bnl as a proprotein that is cleaved by Furin1 in the Golgi. Truncated Bnl sorts asymmetrically to the basal surface, where it is received by cytonemes that extend from the recipient ASP cells. Uncleavable mutant Bnl has signaling activity but is mistargeted to the apical side, reducing its bioavailability. Since Bnl signaling levels feedback control cytoneme production in the ASP, the reduced availability of mutant Bnl on the source basal surface decreases ASP cytoneme numbers, leading to a reduced range of signal/signaling gradient and impaired ASP growth. Thus, enzymatic cleavage ensures polarized intracellular sorting and availability of Bnl to its signaling site, thereby determining its tissue-specific intercellular dispersal and signaling range.

scholarly journals Rho Mediated Mechanical Force Generation Through Dectin-1

2019 ◽  
Vol 116 (3) ◽  
pp. 124a
Author(s):  
Rohan Choraghe ◽  
Alan Buser ◽  
Aaron Neumann
Keyword(s):  
Mechanical Force ◽  
Force Generation

scholarly journals The Impact of Drosophila Awd/NME1/2 Levels on Notch and Wg Signaling Pathways

2020 ◽  
Vol 21 (19) ◽  
pp. 7257
Author(s):  
Giulia Serafini ◽  
Giorgia Giordani ◽  
Luca Grillini ◽  
Davide Andrenacci ◽  
Giuseppe Gargiulo ◽  
...  
Keyword(s):  
Cell Death ◽  
Notch Signaling ◽  
Signaling Pathways ◽  
Target Genes ◽  
Wing Disc ◽  
Amino Terminal ◽  
Disc Cells ◽  
Function Blocks ◽  
The Impact ◽  
Dose Dependent

Awd, the Drosophila homologue of NME1/2 metastasis suppressors, plays key roles in many signaling pathways. Mosaic analysis of the null awdJ2A4 allele showed that loss of awd gene function blocks Notch signaling and the expression of its target genes including the Wingless (Wg/Wnt1) morphogen. We also showed that RNA interference (RNAi)-mediated awd silencing (awdi) in larval wing disc leads to chromosomal instability (CIN) and to Jun amino-terminal kinases (JNK)-mediated cell death. Here we show that this cell death is independent of p53 activity. Based on our previous finding showing that forced survival of awdi-CIN cells leads to aneuploidy without the hyperproliferative effect, we investigated the Wg expression in awdi wing disc cells. Interestingly, the Wg protein is expressed in its correct dorso-ventral domain but shows an altered cellular distribution which impairs its signaling. Further, we show that RNAi-mediated knock down of awd in wing discs does not affect Notch signaling. Thus, our analysis of the hypomorphic phenotype arising from awd downregulation uncovers a dose-dependent effect of Awd in Notch and Wg signaling.

Dissecting the roles of endothelin,TGF-β and GM-CSF on myofibroblast differentiation by keratinocytes

2004 ◽  
Vol 92 (08) ◽  
pp. 262-274 ◽  
Author(s):  
Pierre Shephard ◽  
Boris Hinz ◽  
Sigrun Smola-Hess ◽  
Jean-Jacques Meister ◽  
Thomas Krieg ◽  
...  
Keyword(s):  
Wound Healing ◽  
Smooth Muscle ◽  
Contractile Activity ◽  
Smooth Muscle Actin ◽  
Mechanical Force ◽  
Force Generation ◽  
Epidermal Keratinocytes ◽  
Myofibroblast Differentiation ◽  
Potent Inducer ◽  
Gm Csf

SummaryMyofibroblasts are specialized fibroblasts that contribute to wound healing by producing extracellular matrix and by contracting the granulation tissue.They appear in a phase of wound healing when the dermis strongly interacts with activated epidermal keratinocytes. Direct co-culture with keratinocytes upregulates TGF-β???????????activity and also induces fibroblast to differentiate into α-smooth muscle actin (αSMA)-positive myofibroblasts. TGF-βactivity alone cannot completely account for αSMA induction in these co-cultures, and here we analyze mechanical force generation, another potent inducer of myofibroblast differentiation in this model. Using deformable silicone substrates, we show that contractile activity of fibroblasts is already induced after 1-2-days of co-culture, when fibroblasts are generally αSMA negative. Endothelin-1 (ET-1), the most potent inducer of smooth muscle cell contraction, was up-regulated in co-cultures, while blocking ET-1 with the ET receptor inhibitor PD156252 inhibited contraction in these early co-cultures. In 4-5 days of co-culture, however, fibroblast contractile activity correlated with an increased expression of αSMA expression. Stimulation of fibroblast mono-cultures with ET-1 in a low serum medium did not induce αSMA expression; however, ET-1 did synergize with TGF-β. Surprisingly, GM-CSF, another mediatorstimulating myofibroblast differentiation in granulation tissue, inhibited αSMA expression in fibroblasts, costimulated with TGF-β and ET-1. GM-CSF activated NFκB, thus interfering with TGF-β signaling. Blocking TGF-β and ET-1 largely impaired αSMA induction in co-cultures at day 7 and, in combination, almost completely prevented αSMA induction. Our results dissect the roles of TGF-β and ET-1 on mechanical force generation in keratinocyte-fibroblast co-cultures, and identify GM-CSF as an inducer of myofibroblasts acting indirectly.

scholarly journals Anomalous centriole configurations are detected in Drosophila wing disc cells upon Cdk1 inactivation

2003 ◽  
Vol 116 (1) ◽  
pp. 137-143 ◽  
Author(s):  
S. J. Vidwans
Keyword(s):  
Wing Disc ◽  
Drosophila Wing ◽  
Disc Cells

scholarly journals An Assay to Detect In Vivo Y Chromosome Loss in Drosophila Wing Disc Cells

2012 ◽  
Vol 2 (9) ◽  
pp. 1095-1102 ◽  
Author(s):  
Janos Szabad ◽  
Hugo J. Bellen ◽  
Koen J. T. Venken
Keyword(s):  
Y Chromosome ◽  
Wing Disc ◽  
Chromosome Loss ◽  
Drosophila Wing ◽  
Disc Cells

scholarly journals Domain topology, stability, and translation speed determine mechanical force generation on the ribosome

2018 ◽  
Author(s):  
Sarah E. Leininge ◽  
Fabio Trovato ◽  
Daniel A. Nissley ◽  
Edward P. O’Brien
Keyword(s):  
Protein Synthesis ◽  
Molecular Simulations ◽  
Mechanical Force ◽  
Force Generation ◽  
Coarse Grained ◽  
Mechanical Forces ◽  
Mechanical Modeling ◽  
Translation Speed ◽  
A Cell ◽  
Statistical Mechanical

AbstractThe concomitant folding of a nascent protein domain with its synthesis can generate mechanical forces that act on the ribosome and alter translation speed. Such changes in speed can affect the structure and function of the newly synthesized protein as well as cellular phenotype. The domain properties that govern force generation have yet to be identified and understood, and the influence of translation speed is unknown as all reported measurements have been carried out on arrested ribosomes. Here, using coarse-grained molecular simulations and statistical mechanical modeling of protein synthesis, we demonstrate that force generation is determined by a domain’s stability and topology, as well as translation speed. The statistical mechanical models we create predict how force profiles depend on these properties. These results indicate that force measurements on arrested ribosomes will not always accurately reflect what happens in a cell, especially for slow-folding domains, and suggest the possibility that certain domain properties may be enriched or depleted across the structural proteome of organisms through evolutionary selection pressures to modulate protein synthesis speed and post-translational protein behavior.Significance StatementMechanochemistry, the influence of molecular-scale mechanical forces on chemical processes, can occur on actively translating ribosomes through the force-generating actions of motor proteins and the co-translational folding of domains. Such forces are transmitted to the ribosome’s catalytic core and alter rates of protein synthesis; representing a form of mechanical allosteric communication. These changes in translation-elongation kinetics are biologically important because they can influence protein structure, function, and localization within a cell. Many fundamental questions are unresolved concerning the properties of protein domains that determine mechanical force generation, the effect of translation speed on this force, and exactly how, at the molecular level, force is generated. In this study we answer these questions using cutting-edge molecular simulations and statistical mechanical modeling.

scholarly journals Ectopic expression ofDrosophilaELAV and human HuD inDrosophilawing disc cells reveals functional distinctions and similarities

2002 ◽  
Vol 115 (11) ◽  
pp. 2413-2421 ◽  
Author(s):  
Gakuta Toba ◽  
Jan Qui ◽  
Sandhya P. Koushika ◽  
Kalpana White
Keyword(s):  
Mammalian Cells ◽  
Rna Binding ◽  
Fluorescent Protein ◽  
Rna Binding Proteins ◽  
Mrna Level ◽  
Ectopic Expression ◽  
Wing Disc ◽  
Transcript Stability ◽  
Endogenous Expression ◽  
Disc Cells

Drosophila ELAV and human HuD are two neuronal RNA binding proteins that show remarkable sequence homology, yet differ in their respective documented roles in post-transcriptional regulation. ELAV regulates neural-specific alternative splicing of specific transcripts, and HuD stabilizes specific mRNAs that are otherwise unstable due to AU-rich elements(AREs) in their 3′ untranslated region (UTR). AREs are major determinants of transcript stability in mammalian cells. The role of each of these proteins was investigated and compared, by ectopically expressing them in Drosophila imaginal wing disc cells, which lack endogenous expression of either protein. The effect of the ectopic expression of ELAV and HuD was assessed on two sets of green fluorescent protein reporter transgenes,which were all driven with a broadly expressing promoter. Each set consisted of three reporter transgenes: (1) with an uninterrupted open reading frame(ORF); (2) with a constitutively spliced intron inserted into the ORF; and (3)with the intron nASI whose splicing is regulated in neurons by ELAV,inserted into the ORF. The two sets differed from each other only in their 3′UTR: Heat-shock-protein-70Ab (Hsp70Ab) trailer with ARE-like characteristics or Actin 5C (Act5C) trailer. Our results show that:(1) both ectopically expressed ELAV and HuD can enhance expression of transgenes with the Hsp70Ab 3′UTR, but not of transgenes with Act5C 3′UTR; (2) this enhancement is accompanied by an increase in mRNA level; (3) only ELAV can induce neural-specific splicing of nASI; and (4) although HuD is localized primarily to the cytoplasm,ELAV is localized to both the cytoplasm and the nucleus.

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