Pattern regulation in fragments of Drosophila wing discs which show variable wound healing

Development ◽  
1985 ◽  
Vol 85 (1) ◽  
pp. 95-109
Author(s):  
Leslie Dale ◽  
Mary Bownes

When complementary fragments of the imaginal wing disc of Drosophila are cultured for several days prior to inducing metamorphosis, usually one fragment will regenerate while the second duplicates. It has been proposed that wound healing plays an important part in disc regulation by initiating cell proliferation and determining the mode of regulation (regeneration/duplication). To test the latter proposal 15 types of wing disc fragments were examined for variability both in the mode of wound healing and the mode of pattern regulation. Two modes of wound healing were observed, regular—the two wound edges heal with each other, and irregular—each wound edge heals with itself. When cultured separately fragments that healed regularly regenerated, while fragments that healed irregularly duplicated. This suggests that the mode of wound healing determines the mode of pattern regulation.

Development ◽  
2002 ◽  
Vol 129 (18) ◽  
pp. 4261-4269 ◽  
Author(s):  
Michèle Crozatier ◽  
Bruno Glise ◽  
Alain Vincent

Hedgehog (Hh) signalling from posterior (P) to anterior (A) cells is the primary determinant of AP polarity in the limb field in insects and vertebrates. Hh acts in part by inducing expression of Decapentaplegic (Dpp), but how Hh and Dpp together pattern the central region of the Drosophila wing remains largely unknown. We have re-examined the role played by Collier (Col), a dose-dependent Hh target activated in cells along the AP boundary, the AP organiser in the imaginal wing disc. We found that col mutant wings are smaller than wild type and lack L4 vein, in addition to missing the L3-L4 intervein and mis-positioning of the anterior L3 vein. We link these phenotypes to col requirement for the local upregulation of both emc and N, two genes involved in the control of cell proliferation, the EGFR ligand Vein and the intervein determination gene blistered. We further show that attenuation of Dpp signalling in the AP organiser is also col dependent and, in conjunction with Vein upregulation, required for formation of L4 vein. A model recapitulating the molecular interplay between the Hh, Dpp and EGF signalling pathways in the wing AP organiser is presented.


Author(s):  
J.S. Ryerse

Gap junctions are intercellular junctions found in both vertebrates and invertebrates through which ions and small molecules can pass. Their distribution in tissues could be of critical importance for ionic coupling or metabolic cooperation between cells or for regulating the intracellular movement of growth control and pattern formation factors. Studies of the distribution of gap junctions in mutants which develop abnormally may shed light upon their role in normal development. I report here the distribution of gap junctions in the wing pouch of 3 Drosophila wing disc mutants, vg (vestigial) a cell death mutant, 1(2)gd (lethal giant disc) a pattern abnormality mutant and 1(2)gl (lethal giant larva) a neoplastic mutant and compare these with wildtype wing discs.The wing pouch (the anlagen of the adult wing blade) of a wild-type wing disc is shown in Fig. 1 and consists of columnar cells (Fig. 5) joined by gap junctions (Fig. 6). 14000x EMs of conventionally processed, UA en bloc stained, longitudinally sectioned wing pouches were enlarged to 45000x with a projector and tracings were made on which the lateral plasma membrane (LPM) and gap junctions were marked.


2016 ◽  
Vol 113 (45) ◽  
pp. E6993-E7002 ◽  
Author(s):  
Anupama Hemalatha ◽  
Chaitra Prabhakara ◽  
Satyajit Mayor

Endocytosis of ligand-receptor complexes regulates signal transduction during development. In particular, clathrin and dynamin-dependent endocytosis has been well studied in the context of patterning of the Drosophila wing disc, wherein apically secreted Wingless (Wg) encounters its receptor, DFrizzled2 (DFz2), resulting in a distinctive dorso-ventral pattern of signaling outputs. Here, we directly track the endocytosis of Wg and DFz2 in the wing disc and demonstrate that Wg is endocytosed from the apical surface devoid of DFz2 via a dynamin-independent CLIC/GEEC pathway, regulated by Arf1, Garz, and class I PI3K. Subsequently, Wg containing CLIC/GEEC endosomes fuse with DFz2-containing vesicles derived from the clathrin and dynamin-dependent endocytic pathway, which results in a low pH-dependent transfer of Wg to DFz2 within the merged and acidified endosome to initiate Wg signaling. The employment of two distinct endocytic pathways exemplifies a mechanism wherein cells in tissues leverage multiple endocytic pathways to spatially regulate signaling.


2020 ◽  
Author(s):  
Katrin Strassburger ◽  
Marilena Lutz ◽  
Sandra Müller ◽  
Aurelio A. Teleman

AbstractCells in a developing organ stop proliferating when the organ reaches a correct, final size. The underlying mechanisms are not understood. Although many signaling pathways and cell cycle components are required to sustain cell proliferation, which one of these turns off to terminate proliferation is not known. Here we study proliferation termination using Drosophila wing discs. We extend larval development to provide wing discs a constant growth-sustaining environment, allowing them to terminate proliferation autonomously. We find that the wing pouch, which forms the adult wing blade, terminates proliferation in the absence of brinker or warts, indicating that neither Dpp signaling nor Hippo/Yorkie signaling control final wing size. Instead, termination of proliferation coincides with reduced TORC1 activity and is bypassed by reactivating TORC1. Hence proliferation ceases due to reduced cell growth. Experimental manipulation of Dpp or Yki signaling can bypass proliferation termination in hinge and notum regions, suggesting that the mechanisms regulating proliferation termination may be distinct in different regions of the disc.One Sentence SummaryUsing Drosophila, Strassburger et al. investigate the termination of proliferation of an organ when it reaches its final size, and show this occurs due to a drop in TORC1 signaling.


Development ◽  
1997 ◽  
Vol 124 (15) ◽  
pp. 2973-2981 ◽  
Author(s):  
R.J. Fleming ◽  
Y. Gu ◽  
N.A. Hukriede

In the developing imaginal wing disc of Drosophila, cells at the dorsoventral boundary require localized Notch activity for specification of the wing margin. The Notch ligands Serrate and Delta are required on opposite sides of the presumptive wing margin and, even though activated forms of Notch generate responses on both sides of the dorsoventral boundary, each ligand generates a compartment-specific response. In this report we demonstrate that Serrate, which is expressed in the dorsal compartment, does not signal in the dorsal regions due to the action of the fringe gene product. Using ectopic expression, we show that regulation of Serrate by fringe occurs at the level of protein and not Serrate transcription. Furthermore, replacement of the N-terminal region of Serrate with the corresponding region of Delta abolishes the ability of fringe to regulate Serrate without altering Serrate-specific signaling.


2017 ◽  
Author(s):  
Qinfeng Wu ◽  
Pavel A. Brodskiy ◽  
Francisco Huizar ◽  
Jamison J. Jangula ◽  
Cody Narciso ◽  
...  

AbstractRecently, organ-scale intercellular Ca2+ transients (ICTs) were reported in the Drosophila wing disc. However, the functional in vivo significance of ICTs remains largely unknown. Here we demonstrate the in vivo relevance of intercellular Ca2+ signaling and its impact on wing development. We report that Ca2+ signaling in vivo decreases as wing discs mature. Ca2+ signaling ex vivo responds to fly extract in a dose-dependent manner. This suggests ICTs occur in vivo due to chemical stimulus that varies in concentration during development. RNAi mediated inhibition of genes required for ICTs results in defects in the size, shape, and vein patterning of adult wings. It also leads to reduction or elimination of in vivo Ca2+ transients. Further, perturbations to the extracellular matrix along the basal side of the wing disc stimulates intercellular Ca2+ waves. This is the first identified chemically defined, non-wounding stimulus of ICTs. Together, these results point toward specific in vivo functions of intercellular Ca2+ signaling to mediate mechanical stress dissipation and ensure robust patterning during development.


Development ◽  
2000 ◽  
Vol 127 (11) ◽  
pp. 2383-2393 ◽  
Author(s):  
A. Baonza ◽  
J.F. de Celis ◽  
A. Garcia-Bellido

The function of extramacrochaetae is required during the development of the Drosophila wing in processes such as cell proliferation and vein differentiation. extramacrochaetae encodes a transcription factor of the HLH family, but unlike other members of this family, Extramacrochaetae lacks the basic region that is involved in interaction with DNA. Some phenotypes caused by extramacrochaetae in the wing are similar to those observed when Notch signalling is compromised. Furthermore, maximal levels of extramacrochaetae expression in the wing disc are restricted to places where Notch activity is higher, suggesting that extramacrochaetae could mediate some aspects of Notch signalling during wing development. We have studied the relationships between extramacrochaetae and Notch in wing development, with emphasis on the processes of vein formation and cell proliferation. We observe strong genetic interaction between extramacrochaetae and different components of the Notch signalling pathway, suggesting a functional relationship between them. We show that the higher level of extramacrochaetae expression coincides with the domain of expression of Notch and its downstream gene Enhancer of split-m(beta). The expression of extramacrochaetae at the dorso/ventral boundary and in boundary cells between veins and interveins depends on Notch activity. We propose that at least during vein differentiation and wing margin formation, extramacrochaetae is regulated by Notch and collaborates with other Notch-downstream genes such as Enhancer of split-m(beta).


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