A dual role for homothorax in inhibiting wing blade development and specifying proximal wing identities in Drosophila

Development ◽  
2000 ◽  
Vol 127 (7) ◽  
pp. 1499-1508 ◽  
Author(s):  
F. Casares ◽  
R.S. Mann
Keyword(s):  
Signal Transduction ◽  
Imaginal Disc ◽  
Target Genes ◽  
Notch Pathway ◽  
Wing Disc ◽  
Signal Transduction Pathways ◽  
Body Parts ◽  
Drosophila Wing ◽  
Compartment Boundary ◽  
Three Body

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.

Control of growth and patterning of the Drosophila wing imaginal disc by EGFR-mediated signaling

Development ◽  
2002 ◽  
Vol 129 (6) ◽  
pp. 1369-1376 ◽  
Author(s):  
Myriam Zecca ◽  
Gary Struhl
Keyword(s):  
Gene Expression ◽  
Imaginal Disc ◽  
Ectopic Expression ◽  
Growth Factor Receptor ◽  
Wing Disc ◽  
Wing Imaginal Disc ◽  
Egfr Signaling ◽  
Drosophila Wing ◽  
Compartment Boundary ◽  
Egfr Ligand

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.

scholarly journals Regulated delivery controls Drosophila Hedgehog, Wingless and Decapentaplegic signaling

2020 ◽  
Author(s):  
Ryo Hatori ◽  
Thomas B. Kornberg
Keyword(s):  
Signal Transduction ◽  
Imaginal Disc ◽  
Wing Disc ◽  
Bone Morphogenic Protein ◽  
Wing Imaginal Disc ◽  
Target Cells ◽  
Signaling Proteins ◽  
Common Pool ◽  
Drosophila Wing ◽  
Disc Cells

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.

Subdivision of the Drosophila wing imaginal disc by EGFR-mediated signaling

Development ◽  
2002 ◽  
Vol 129 (6) ◽  
pp. 1357-1368 ◽  
Author(s):  
Myriam Zecca ◽  
Gary Struhl
Keyword(s):  
Imaginal Disc ◽  
Growth Factor Receptor ◽  
Subsequent Development ◽  
Wing Disc ◽  
Wing Imaginal Disc ◽  
Egfr Signaling ◽  
Drosophila Wing ◽  
Compartment Boundary ◽  
Epidermal Growth ◽  
Necessary And Sufficient

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.

Regeneration from duplicating fragments of the Drosophila wing disc

Development ◽  
1981 ◽  
Vol 66 (1) ◽  
pp. 117-126
Author(s):  
Jane Karlsson ◽  
R. J. Smith
Keyword(s):  
Imaginal Disc ◽  
General Rule ◽  
Wing Disc ◽  
The Other ◽  
Posterior Compartment ◽  
Drosophila Wing ◽  
Polar Coordinate ◽  
New Type ◽  
Coordinate Model

It is a general rule that of two complementary Drosophila imaginal disc fragments, one regenerates and the other duplicates. This paper reports an investigation of an exception to this rule. Duplicating fragments from the periphery of the wing disc which lacked presumptive notum were found to regenerate notum structures during and after duplication. The propensity for this was greatest in fragments lying close to the presumptive notum, with the exception of a fragment confined to the posterior compartment, which did not regenerate notum. Structures were added sequentially, and regeneration stopped once most of the notum was present. These results are not easily explained by the polar coordinate model, which states that regeneration cannot occur from duplicating fragments. Since compartments appear to be involved in this type of regeneration as in others, it is suggested that a new type of model is required, one which permits simultaneous regeneration and duplication, and assigns a major role to compartments.

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 knot (kn) in Wing Patterning in Drosophila

Genetics ◽  
1997 ◽  
Vol 147 (3) ◽  
pp. 1203-1212 ◽  
Author(s):  
Katerina Nestoras ◽  
Helena Lee ◽  
Jym Mohler
Keyword(s):  
Hedgehog Signaling ◽  
Imaginal Disc ◽  
Hedgehog Signaling Pathway ◽  
Posterior Compartment ◽  
Drosophila Wing ◽  
Compartment Boundary ◽  
Hh Signaling ◽  
Embryonic Segmentation ◽  
Anterior Posterior

We have undertaken a genetic analysis of new strong alleles of knot (kn). The original kn1 mutation causes an alteration of wing patterning similar to that associated with mutations of fused (fu), an apparent fusion of veins 3 and 4 in the wing. However, unlike fu, strong kn mutations do not affect embryonic segmentation and indicate that kn is not a component of a general Hh (Hedgehog)-signaling pathway. Instead we find that kn has a specific role in those cells of the wing imaginal disc that are subject to ptc-mediated Hh-signaling. Our results suggest a model for patterning the medial portion of the Drosophila wing, whereby the separation of veins 3 and 4 is maintained by kn activation in the intervening region in response to Hh-signaling across the adjacent anterior-posterior compartment boundary.

Expression and function of decapentaplegic and thick veins during the differentiation of the veins in the Drosophila wing

Development ◽  
1997 ◽  
Vol 124 (5) ◽  
pp. 1007-1018 ◽  
Author(s):  
J.F. Celis de
Keyword(s):  
Imaginal Disc ◽  
Signal Transduction Pathways ◽  
Pupal Development ◽  
Transmembrane Receptors ◽  
Notch Ligand ◽  
Regulatory Interactions ◽  
Drosophila Wing ◽  
Signalling Molecule ◽  
And Function

The differentiation of the veins in the Drosophila wing involves the coordinate activities of several signal transduction pathways, including those mediated by the transmembrane receptors Torpedo and Notch. In this report, the role of the signalling molecule Decapentaplegic during vein differentiation has been analysed. It is shown that decapentaplegic is expressed in the pupal veins under the control of genes that establish vein territories in the imaginal disc. Decapentaplegic, acting through its receptor Thick veins, activates vein differentiation and restricts expression of both veinlet and the Notch-ligand Delta to the developing veins. Genetic combinations between mutations that increase or reduce Notch, veinlet and decapentaplegic activities suggest that the maintenance of the vein differentiation state during pupal development involves cross-regulatory interactions between these pathways.

scholarly journals Regulatory Network Connecting Two Glucose Signal Transduction Pathways in Saccharomyces cerevisiae

2004 ◽  
Vol 3 (1) ◽  
pp. 221-231 ◽  
Author(s):  
Aneta Kaniak ◽  
Zhixiong Xue ◽  
Daniel Macool ◽  
Jeong-Ho Kim ◽  
Mark Johnston
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Signal Transduction ◽  
Transcription Factor ◽  
Regulatory Network ◽  
Target Genes ◽  
Glucose Repression ◽  
Signal Transduction Pathways ◽  
Glucose Signaling ◽  
Genes Encoding ◽  
Glucose Induction

ABSTRACT The yeast Saccharomyces cerevisiae senses glucose, its preferred carbon source, through multiple signal transduction pathways. In one pathway, glucose represses the expression of many genes through the Mig1 transcriptional repressor, which is regulated by the Snf1 protein kinase. In another pathway, glucose induces the expression of HXT genes encoding glucose transporters through two glucose sensors on the cell surface that generate an intracellular signal that affects function of the Rgt1 transcription factor. We profiled the yeast transcriptome to determine the range of genes targeted by this second pathway. Candidate target genes were verified by testing for Rgt1 binding to their promoters by chromatin immunoprecipitation and by measuring the regulation of the expression of promoter lacZ fusions. Relatively few genes could be validated as targets of this pathway, suggesting that this pathway is primarily dedicated to regulating the expression of HXT genes. Among the genes regulated by this glucose signaling pathway are several genes involved in the glucose induction and glucose repression pathways. The Snf3/Rgt2-Rgt1 glucose induction pathway contributes to glucose repression by inducing the transcription of MIG2, which encodes a repressor of glucose-repressed genes, and regulates itself by inducing the expression of STD1, which encodes a regulator of the Rgt1 transcription factor. The Snf1-Mig1 glucose repression pathway contributes to glucose induction by repressing the expression of SNF3 and MTH1, which encodes another regulator of Rgt1, and also regulates itself by repressing the transcription of MIG1. Thus, these two glucose signaling pathways are intertwined in a regulatory network that serves to integrate the different glucose signals operating in these two pathways.

scholarly journals Insights into Functional Connectivity in Mammalian Signal Transduction Pathways by Pairwise Comparison of Protein Interaction Partners of Critical Signaling Hubs

2019 ◽  
Author(s):  
Chilakamarti V. Ramana
Keyword(s):  
Signal Transduction ◽  
Transcription Factors ◽  
Functional Connectivity ◽  
Protein Interaction ◽  
Target Genes ◽  
Pairwise Comparison ◽  
Signal Transduction Pathways ◽  
Critical Nodes ◽  
Interaction Partners ◽  
Signaling Modules

AbstractGrowth factors and cytokines activate signal transduction pathways and regulate gene expression in eukaryotes. Intracellular domains of activated receptors recruit several protein kinases as well as transcription factors that serve as platforms or hubs for the assembly of multi-protein complexes. The signaling hubs involved in a related biologic function often share common interaction proteins and target genes. This functional connectivity suggests that a pairwise comparison of protein interaction partners of signaling hubs and network analysis of common partners and their expression analysis might lead to the identification of critical nodes in cellular signaling. A pairwise comparison of signaling hubs across several related pathways might also reveal novel signaling modules. Analysis of Protein Interaction Connectome by Venn (PIC-VENN) of transcription factors STAT1, STAT3, NFKB1, RELA, FOS and JUN, and their common interaction network suggested that BRCA1 and TSC22D3 function as critical nodes in immune responses by connecting the signaling nodes into signaling modules. Mutations or differential expression levels of these critical nodes in pathological conditions might deregulate signaling pathways and their target genes involved in inflammation. Biological connectivity emerges from the structural connectivity of interaction networks across several signaling hubs in related pathways. Application of PIC-VENN to several signaling hubs might reveal novel nodes and modules that can be targeted to simultaneously activate or inhibit cell signaling in health and disease.

scholarly journals msh specifies dorsal cell fate in the Drosophila wing

Development ◽  
2001 ◽  
Vol 128 (17) ◽  
pp. 3263-3268 ◽  
Author(s):  
Marco Milán ◽  
Ulrich Weihe ◽  
Stanley Tiong ◽  
Welcome Bender ◽  
Stephen M. Cohen
Keyword(s):  
Cell Fate ◽  
Imaginal Disc ◽  
Homeobox Gene ◽  
Wing Imaginal Disc ◽  
Wing Development ◽  
Drosophila Wing ◽  
Compartment Boundary ◽  
Signaling Center ◽  
Dorsal Cells ◽  
Dorsal Cell Fate

Drosophila limbs develop from imaginal discs that are subdivided into compartments. Dorsal-ventral subdivision of the wing imaginal disc depends on apterous activity in dorsal cells. Apterous protein is expressed in dorsal cells and is responsible for (1) induction of a signaling center along the dorsal-ventral compartment boundary (2) establishment of a lineage restriction boundary between compartments and (3) specification of dorsal cell fate. Here, we report that the homeobox gene msh (muscle segment homeobox) acts downstream of apterous to confer dorsal identity in wing development.

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