scholarly journals Hedgehog produced by the Drosophila wing imaginal disc induces distinct responses in three target tissues

Development ◽  
2020 ◽  
Vol 147 (22) ◽  
pp. dev195974
Author(s):  
Ryo Hatori ◽  
Thomas B. Kornberg

ABSTRACTHedgehog (Hh) is an evolutionarily conserved signaling protein that has essential roles in animal development and homeostasis. We investigated Hh signaling in the region of the Drosophila wing imaginal disc that produces Hh and is near the tracheal air sac primordium (ASP) and myoblasts. Hh distributes in concentration gradients in the anterior compartment of the wing disc, ASP and myoblasts, and activates genes in each tissue. Some targets of Hh signal transduction are common to the disc, ASP and myoblasts, whereas others are tissue-specific. Signaling in the three tissues is cytoneme-mediated and cytoneme-dependent. Some ASP cells project cytonemes that receive both Hh and Branchless (Bnl), and some targets regulated by Hh signaling in the ASP are also dependent on Bnl signal transduction. We conclude that the single source of Hh in the wing disc regulates cell type-specific responses in three discreet target tissues.

2020 ◽  
Author(s):  
Ryo Hatori ◽  
Thomas B. Kornberg

AbstractHedgehog (Hh) is an evolutionarily conserved signaling protein that has essential roles in animal development and homeostasis. We investigated Hh signaling in the region of the Drosophila wing imaginal disc that produces Hh and is near the tracheal air sac primordium (ASP) and myoblasts. Hh distributes in concentration gradients in the wing disc anterior compartment, ASP, and myoblasts and activates different sets of genes in each tissue. Some transcriptional targets of Hh signal transduction are common to the disc, ASP, and myoblasts, whereas others are tissue-specific. Signaling in the three tissues is cytoneme-mediated and cytoneme-dependent. We conclude that a single source of Hh in the wing disc regulates cell type-specific responses in three discreet target tissues.SummaryHedgehog produced by the wing imaginal disc signals to wing disc, myoblast and tracheal cells


2020 ◽  
Author(s):  
Ryo Hatori ◽  
Thomas B. Kornberg

AbstractMorphogen signaling proteins disperse across tissues to activate signal transduction in target cells. We investigated dispersion of Hedgehog (Hh), Wingless (Wg), and Bone morphogenic protein homolog Decapentaplegic (Dpp) in the Drosophila wing imaginal disc, and found that delivery to targets is regulated. Cells take up <5% Hh produced, and neither amounts taken up nor extent of signaling changes under conditions of Hh production from 50-200% normal amounts. Similarly, cells take up <25% Wg produced, and variation in Wg production from 50-700% normal has no effect on amounts taken up or signaling. Similar properties were observed for Dpp. Wing disc-produced Hh signals to disc-associated tracheal and myoblast as well as an approximately equal number of disc cells, but the extent of signaling in the disc is unaffected by the presence or absence of the tracheal cells and myoblasts. These findings show that target cells do not take up signaling proteins from a common pool and that both the amount and destination of delivered morphogens are regulated..SummaryThe extent of Hh, Wg, and Dpp signaling is independent of the amount of signal produced or the number of recipient cells.


Development ◽  
2002 ◽  
Vol 129 (6) ◽  
pp. 1369-1376 ◽  
Author(s):  
Myriam Zecca ◽  
Gary Struhl

The subdivision of the Drosophila wing imaginal disc into dorsoventral (DV) compartments and limb-body wall (wing-notum) primordia depends on Epidermal Growth Factor Receptor (EGFR) signaling, which heritably activates apterous (ap) in D compartment cells and maintains Iroquois Complex (Iro-C) gene expression in prospective notum cells. We examine the source, identity and mode of action of the EGFR ligand(s) that specify these subdivisions. Of the three known ligands for the Drosophila EGFR, only Vein (Vn), but not Spitz or Gurken, is required for wing disc development. We show that Vn activity is required specifically in the dorsoproximal region of the wing disc for ap and Iro-C gene expression. However, ectopic expression of Vn in other locations does not reorganize ap or Iro-C gene expression. Hence, Vn appears to play a permissive rather than an instructive role in organizing the DV and wing-notum segregations, implying the existance of other localized factors that control where Vn-EGFR signaling is effective. After ap is heritably activated, the level of EGFR activity declines in D compartment cells as they proliferate and move ventrally, away from the source of the instructive ligand. We present evidence that this reduction is necessary for D and V compartment cells to interact along the compartment boundary to induce signals, like Wingless (Wg), which organize the subsequent growth and differentiation of the wing primordium.


Development ◽  
2000 ◽  
Vol 127 (7) ◽  
pp. 1499-1508 ◽  
Author(s):  
F. Casares ◽  
R.S. Mann

The Drosophila wing imaginal disc gives rise to three body parts along the proximo-distal (P-D) axis: the wing blade, the wing hinge and the mesonotum. Development of the wing blade initiates along part of the dorsal/ventral (D/V) compartment boundary and requires input from both the Notch and wingless (wg) signal transduction pathways. In the wing blade, wg activates the gene vestigial (vg), which is required for the wing blade to grow. wg is also required for hinge development, but wg does not activate vg in the hinge, raising the question of what target genes are activated by wg to generate hinge structures. Here we show that wg activates the gene homothorax (hth) in the hinge and that hth is necessary for hinge development. Further, we demonstrate that hth also limits where along the D/V compartment boundary wing blade development can initiate, thus helping to define the size and position of the wing blade within the disc epithelium. We also show that the gene teashirt (tsh), which is coexpressed with hth throughout most of wing disc development, collaborates with hth to repress vg and block wing blade development. Our results suggest that tsh and hth block wing blade development by repressing some of the activities of the Notch pathway at the D/V compartment boundary.


Development ◽  
2002 ◽  
Vol 129 (6) ◽  
pp. 1357-1368 ◽  
Author(s):  
Myriam Zecca ◽  
Gary Struhl

Growth and patterning of the Drosophila wing imaginal disc depends on its subdivision into dorsoventral (DV) compartments and limb (wing) and body wall (notum) primordia. We present evidence that both the DV and wing-notum subdivisions are specified by activation of the Drosophila Epidermal Growth Factor Receptor (EGFR). We show that EGFR signaling is necessary and sufficient to activate apterous (ap) expression, thereby segregating the wing disc into D (ap-ON) and V (ap-OFF) compartments. Similarly, we demonstrate that EGFR signaling directs the expression of Iroquois Complex (Iro-C) genes in prospective notum cells, rendering them distinct from, and immiscible with, neighboring wing cells. However, EGFR signaling acts only early in development to heritably activate ap, whereas it is required persistently during subsequent development to maintain Iro-C gene expression. Hence, as the disc grows, the DV compartment boundary can shift ventrally, beyond the range of the instructive EGFR signal(s), in contrast to the notum-wing boundary, which continues to be defined by EGFR input.


2000 ◽  
Vol 6 (2) ◽  
pp. 479-485 ◽  
Author(s):  
F.-A. Ramírez-Weber ◽  
D.J. Casso ◽  
P. Aza-Blanc ◽  
T. Tabata ◽  
T.B. Kornberg

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Hai Huang ◽  
Thomas B Kornberg

The flight muscles, dorsal air sacs, wing blades, and thoracic cuticle of the Drosophila adult function in concert, and their progenitor cells develop together in the wing imaginal disc. The wing disc orchestrates dorsal air sac development by producing decapentaplegic and fibroblast growth factor that travel via specific cytonemes in order to signal to the air sac primordium (ASP). Here, we report that cytonemes also link flight muscle progenitors (myoblasts) to disc cells and to the ASP, enabling myoblasts to relay signaling between the disc and the ASP. Frizzled (Fz)-containing myoblast cytonemes take up Wingless (Wg) from the disc, and Delta (Dl)-containing myoblast cytonemes contribute to Notch activation in the ASP. Wg signaling negatively regulates Dl expression in the myoblasts. These results reveal an essential role for cytonemes in Wg and Notch signaling and for a signal relay system in the myoblasts.


eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Lijuan Du ◽  
Alex Sohr ◽  
Ge Yan ◽  
Sougata Roy

Gradients of signaling proteins are essential for inducing tissue morphogenesis. However, mechanisms of gradient formation remain controversial. Here we characterized the distribution of fluorescently-tagged signaling proteins, FGF and FGFR, expressed at physiological levels from the genomic knock-in alleles in Drosophila. FGF produced in the larval wing imaginal-disc moves to the air-sac-primordium (ASP) through FGFR-containing cytonemes that extend from the ASP to contact the wing-disc source. The number of FGF-receiving cytonemes extended by ASP cells decreases gradually with increasing distance from the source, generating a recipient-specific FGF gradient. Acting as a morphogen in the ASP, FGF activates concentration-dependent gene expression, inducing pointed-P1 at higher and cut at lower levels. The transcription-factors Pointed-P1 and Cut antagonize each other and differentially regulate formation of FGFR-containing cytonemes, creating regions with higher-to-lower numbers of FGF-receiving cytonemes. These results reveal a robust mechanism where morphogens self-generate precise tissue-specific gradient contours through feedback regulation of cytoneme-mediated dispersion.


eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Ryo Hatori ◽  
Brent M Wood ◽  
Guilherme Oliveira Barbosa ◽  
Thomas B Kornberg

Morphogen signaling proteins disperse across tissues to activate signal transduction in target cells. We investigated dispersion of Hedgehog (Hh), Wnt homolog Wingless (Wg), and Bone morphogenic protein homolog Decapentaplegic (Dpp) in the Drosophila wing imaginal disc. We discovered that delivery of Hh, Wg, and Dpp to their respective targets is regulated. We found that <5% of Hh and <25% of Wg are taken up by disc cells and activate signaling. The amount of morphogen that is taken up and initiates signaling did not change when the level of morphogen expression was varied between 50-200% (Hh) or 50-350% (Wg). Similar properties were observed for Dpp. We analyzed an area of 150 mm x 150 mm that includes Hh-responding cells of the disc as well as overlying tracheal cells and myoblasts that are also activated by disc-produced Hh. We found that the extent of signaling in the disc was unaffected by the presence or absence of the tracheal and myoblast cells, suggesting that the mechanism that disperses Hh specifies its destinations to particular cells, and that target cells do not take up Hh from a common pool.


2021 ◽  
Author(s):  
Ioannis Nellas ◽  
K. Venkatesan Iyer ◽  
Juan M. Iglesias-Artola ◽  
André Nadler ◽  
Natalie A. Dye ◽  
...  

ABSTRACTEnergy production and utilization is critically important for animal development and growth. How it is regulated in space and time during tissue growth remains largely unclear. Toward this end, we used a FRET-based adenosine triphosphate (ATP) sensor to dynamically monitor ATP levels across a growing tissue, using the Drosophila wing disc. We discovered that steady-state levels of ATP are spatially uniform across the wing pouch. Pharmacologically inhibiting oxidative phosphorylation, however, reveals spatial heterogeneities in metabolic behavior, whereby signaling centers at compartment boundaries produce more ATP from glycolysis than the rest of the tissue. Genetic perturbations indicate that the conserved Hedgehog (Hh) signaling pathway can enhance ATP production by glycolysis. Collectively, our work reveals a positive feedback loop between Hh signaling and energy metabolism, advancing our understanding of the connection between conserved developmental patterning genes and energy production during animal tissue development.


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