Quantitative EM of gap junction distribution in mutant drosophila wing discs

1983 ◽  
Vol 41 ◽  
pp. 720-721
Author(s):  
J.S. Ryerse
Keyword(s):  
Gap Junctions ◽  
Growth Control ◽  
Intercellular Junctions ◽  
Wing Disc ◽  
En Bloc ◽  
Metabolic Cooperation ◽  
Drosophila Wing ◽  
Adult Wing ◽  
Wing Discs ◽  
Wing Pouch

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.

scholarly journals Autonomous termination of proliferation in the Drosophila wing disc is TORC1 dependent

2020 ◽  
Author(s):  
Katrin Strassburger ◽  
Marilena Lutz ◽  
Sandra Müller ◽  
Aurelio A. Teleman
Keyword(s):  
Experimental Manipulation ◽  
Wing Disc ◽  
Wing Size ◽  
Final Size ◽  
Drosophila Wing ◽  
Adult Wing ◽  
Wing Discs ◽  
Underlying Mechanisms ◽  
Constant Growth ◽  
Wing Pouch

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.

scholarly journals Endocytosis of Wingless via a dynamin-independent pathway is necessary for signaling in Drosophila wing discs

2016 ◽  
Vol 113 (45) ◽  
pp. E6993-E7002 ◽  
Author(s):  
Anupama Hemalatha ◽  
Chaitra Prabhakara ◽  
Satyajit Mayor
Keyword(s):  
Signal Transduction ◽  
Wing Disc ◽  
Low Ph ◽  
Endocytic Pathway ◽  
Apical Surface ◽  
Receptor Complexes ◽  
Drosophila Wing ◽  
Wing Discs ◽  
Ph Dependent ◽  
Endocytic Pathways

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.

Role of the EGF receptor pathway in growth and patterning of the Drosophila wing through the regulation of vestigial

Development ◽  
1999 ◽  
Vol 126 (5) ◽  
pp. 975-985 ◽  
Author(s):  
R. Nagaraj ◽  
A.T. Pickup ◽  
R. Howes ◽  
K. Moses ◽  
M. Freeman ◽  
...  
Keyword(s):  
Egf Receptor ◽  
Regulatory Gene ◽  
Ectopic Expression ◽  
Wing Disc ◽  
Loss Of Function ◽  
Drosophila Wing ◽  
Expression Studies ◽  
Coordinated Expression ◽  
Wing Pouch

Growth and patterning of the Drosophila wing disc depends on the coordinated expression of the key regulatory gene vestigial both in the Dorsal-Ventral (D/V) boundary cells and in the wing pouch. We propose that a short-range signal originating from the core of the D/V boundary cells is responsible for activating EGFR in a zone of organizing cells on the edges of the D/V boundary. Using loss-of-function mutations and ectopic expression studies, we show that EGFR signaling is essential for vestigial transcription in these cells and for making them competent to undergo subsequent vestigial-mediated proliferation within the wing pouch.

Repression of Teashirt marks the initiation of wing development

Development ◽  
2002 ◽  
Vol 129 (10) ◽  
pp. 2411-2418 ◽  
Author(s):  
Jun Wu ◽  
Stephen M. Cohen
Keyword(s):  
Body Wall ◽  
Larval Instar ◽  
Wing Disc ◽  
Wing Development ◽  
Homeodomain Protein ◽  
Zinc Finger Transcription Factor ◽  
Adult Wing ◽  
Combined Action ◽  
Wing Pouch ◽  
Early Activity

The wing imaginal disc comprises the primordia of the adult wing and the dorsal thoracic body wall. During second larval instar, the wing disc is subdivided into distinct domains that correspond to the presumptive wing and body wall. Early activity of the signaling protein Wingless has been implicated in the specification of the wing primordium. Wingless mutants can produce animals in which the wing is replaced by a duplication of thoracic structures. Specification of wing fate has been visualized by expression of the POU-homeodomain protein Nubbin in the presumptive wing territory and by repression of the homeodomain protein Homothorax. We report that repression of the zinc-finger transcription factor Teashirt (Tsh) is the earliest event in wing specification. Repression of Tsh by the combined action of Wingless and Decapentaplegic is required for wing pouch formation and for subsequent repression of Hth. Thus, repression of Tsh defines the presumptive wing earlier in development than repression of Hth, which must therefore be considered a secondary event.

scholarly journals A FINE STRUCTURAL ANALYSIS OF INTERCELLULAR JUNCTIONS IN THE MOUSE LIVER

1970 ◽  
Vol 45 (2) ◽  
pp. 272-290 ◽  
Author(s):  
Daniel A. Goodenough ◽  
Jean Paul Revel
Keyword(s):  
Gap Junctions ◽  
Mouse Liver ◽  
Intercellular Junctions ◽  
Uranyl Acetate ◽  
Bile Canaliculus ◽  
Negative Staining ◽  
En Bloc ◽  
Intact Mouse ◽  
Zonula Occludens ◽  
Staining Techniques

Zonulae occludentes and gap junctions were examined both in the intact mouse liver and in a junction-rich membrane fraction from homogenized mouse liver. These preparations were visualized with the techniques of uranyl acetate staining en bloc, staining with colloidal lanthanum, negative staining with phosphotungstate, and freeze-cleaving. The zonula occludens is arranged as a meshwork of branching and anastomosing threadlike contacts sealing the lumen of the bile canaliculus from the liver intercellular space. The gap junction is characterized in section by a 20 A gap between the apposed junctional membrane outer leaflets, and permeation of this space with lanthanum or phosphotungstate reveals a polygonal lattice of subunits with a center-to-center spacing of 90–100 A. Freeze-cleaved gap junctions show a similar lattice. Extraction of junction-rich fractions with 60% aqueous acetone results in a disappearance of the 20 A gap in sectioned pellets and an inability to demonstrate the polygonal lattice with either the freeze-cleave or negative staining techniques. Extraction of the membranes with 50% acetone does not produce this effect. Thin-layer chromatography of the acetone extracts reveals a group of phospholipids in the 60% extract that are not detectable in the 50% extract. Acetone does not cause any detectable change in the structure of the zonula occludens, but the occluding junction becomes leaky to lanthanum following acetone treatment. The effects of other reagents on the junctions are reported.

Drosophila Lyra Mutations Are Gain-of-Function Mutations of senseless

Genetics ◽  
2001 ◽  
Vol 157 (1) ◽  
pp. 307-315 ◽  
Author(s):  
Riitta Nolo ◽  
Lois A Abbott ◽  
Hugo J Bellen
Keyword(s):  
Apoptotic Cell ◽  
Ectopic Expression ◽  
Wing Disc ◽  
Brdu Incorporation ◽  
Wing Margin ◽  
Aberrant Expression ◽  
Severe Reduction ◽  
Wing Discs ◽  
Necessary And Sufficient ◽  
Wing Pouch

Abstract The Lyra mutation was first described by Jerry Coyne in 1935. Lyra causes recessive pupal lethality and adult heterozygous Lyra mutants exhibit a dominant loss of the anterior and posterior wing margins. Unlike many mutations that cause loss of wing tissue (e.g., scalloped, Beadex, cut, and apterous-Xasta), Lyra wing discs do not exhibit increased necrotic or apoptotic cell death, nor do they show altered BrdU incorporation. However, during wing disc eversion, loss of the anterior and posterior wing margins is apparent. We have previously shown that senseless, a gene that is necessary and sufficient for peripheral nervous system (PNS) development, is allelic to Lyra. Here we show by several genetic criteria that Lyra alleles are neomorphic alleles of senseless that cause ectopic expression of SENSELESS in the wing pouch. Similarly, overexpression of SENSELESS in the wing disc causes loss of wing margin tissue, thereby mimicking the Lyra phenotype. Lyra mutants display aberrant expression of DELTA, VESTIGIAL, WINGLESS, and CUT. As in Lyra mutants, overexpression of SENSELESS in some areas of the wing pouch also leads to loss of WINGLESS and CUT. In summary, our data indicate that overexpression of SENSELESS causes a severe reduction in NOTCH signaling that in turn may lead to decreased transcription of several key genes required for wing development, leading to a failure in cell proliferation and loss of wing margin tissue.

Acquisition of differentiative capacity in imaginal wing discs of Drosophila melanogaster

Development ◽  
1979 ◽  
Vol 49 (1) ◽  
pp. 103-113
Author(s):  
Mary Bownes ◽  
Sarah Roberts
Keyword(s):  
Drosophila Melanogaster ◽  
Wing Disc ◽  
Incomplete Form ◽  
Adult Wing ◽  
Wing Discs ◽  
Derivatives Of ◽  
Development Proceeds

The wing discs from larvae undergoing the moult fiom 1st to 2nd instar are able to differentiate some parts of the adult wing when forced to undergo a premature metamorphosis. The first structures which differentiate are parts of the wing hinge and the wing blade. As development proceeds and older discs are forced through metamorphosis, the capacity to differentiate moves out both proximally and distally until gradually all of the derivatives of a mature wing disc are formed. Individual structures often differentiate from young discs in an incomplete form and pattern elements, such as bristles or sensilla, are added as older discs are tested.

scholarly journals In vivo relevance of intercellular calcium signaling in Drosophila wing development

2017 ◽  
Author(s):  
Qinfeng Wu ◽  
Pavel A. Brodskiy ◽  
Francisco Huizar ◽  
Jamison J. Jangula ◽  
Cody Narciso ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Wing Disc ◽  
Chemical Stimulus ◽  
Wing Development ◽  
Dependent Manner ◽  
Drosophila Wing ◽  
Wing Discs ◽  
Vein Patterning ◽  
Dose Dependent

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.

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
Keyword(s):  
Cell Proliferation ◽  
Wound Healing ◽  
Wing Disc ◽  
Wound Edge ◽  
Drosophila Wing ◽  
Imaginal Wing Disc ◽  
Wing Discs ◽  
Pattern Regulation ◽  
Mode Of Regulation

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.

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