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.

Creating a Drosophila wing de novo, the role of engrailed, and the compartment border hypothesis

Development ◽  
1995 ◽  
Vol 121 (10) ◽  
pp. 3359-3369 ◽  
Author(s):  
T. Tabata ◽  
C. Schwartz ◽  
E. Gustavson ◽  
Z. Ali ◽  
T.B. Kornberg
Keyword(s):  
Imaginal Disc ◽  
De Novo ◽  
Posterior Compartment ◽  
Anterior Compartment ◽  
Drosophila Wing ◽  
Organizational Feature ◽  
Wing Discs ◽  
Mutant Cells ◽  
Anterior Posterior

Anterior/posterior compartment borders bisect every Drosophila imaginal disc, and the engrailed gene is essential for their function. We analyzed the role of the engrailed and invected genes in wing discs by eliminating or increasing their activity. Removing engrailed/invected from posterior wing cells created two new compartments: an anterior compartment consisting of mutant cells and a posterior compartment that grew from neighboring cells. In some cases, these compartments formed a complete new wing. Increasing engrailed activity also affected patterning. These findings demonstrate that engrailed both directs the posterior compartment pathway and creates the compartment border. These findings also establish the compartment border as the pre-eminent organizational feature of disc growth and patterning.

engrailed and polyhomeotic interactions are required to maintain the A/P boundary of the Drosophila developing wing

Development ◽  
1998 ◽  
Vol 125 (15) ◽  
pp. 2771-2780 ◽  
Author(s):  
F. Maschat ◽  
N. Serrano ◽  
N.B. Randsholt ◽  
G. Geraud
Keyword(s):  
Cell Fate ◽  
Regulatory Protein ◽  
Polycomb Group ◽  
Posterior Compartment ◽  
Cubitus Interruptus ◽  
Anterior Compartment ◽  
Embryonic Segmentation ◽  
Wing Morphogenesis ◽  
Anterior Posterior

Engrailed is a nuclear regulatory protein with essential roles in embryonic segmentation and wing morphogenesis. One of its regulatory targets in embryos was shown to be the Polycomb group gene, polyhomeotic. We show here that transheterozygous adult flies, mutant for both engrailed and polyhomeotic, show a gap in the fourth vein. In the corresponding larval imaginal discs, a polyhomeotic-lacZ enhancer trap is not normally activated in anterior cells adjacent to the anterior-posterior boundary. This intermediary region corresponds to the domain of low engrailed expression that appears in the anterior compartment, during L3. Several arguments show that engrailed is responsible for the induction of polyhomeotic in these cells. The role of polyhomeotic in this intermediary region is apparently to maintain the repression of hedgehog in the anterior cells abutting the anterior-posterior boundary, since these cells ectopically express hedgehog when polyhomeotic is not activated. This leads to ectopic expressions first of patched, then of cubitus interruptus and decapentaplegic in the posterior compartment, except for the dorsoventral border cells that are not affected. Thus posterior cells express a new set of genes that are normally characteristic of anterior cells, suggesting a change in the cell identity. Altogether, our data indicate that engrailed and polyhomeotic interactions are required to maintain the anterior-posterior boundary and the posterior cell fate, just prior to the evagination of the wing.

scholarly journals The Hedgehog Signaling Pathway in Ischemic Tissues

2019 ◽  
Vol 20 (21) ◽  
pp. 5270 ◽  
Author(s):  
Igor Giarretta ◽  
Eleonora Gaetani ◽  
Margherita Bigossi ◽  
Paolo Tondi ◽  
Takayuki Asahara ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Tissue Regeneration ◽  
Hedgehog Signaling ◽  
Potential Role ◽  
Hedgehog Signaling Pathway ◽  
Pathological Conditions ◽  
Ischemic Tissue ◽  
Hh Signaling ◽  
The Brain

Hedgehog (Hh) proteins are prototypical morphogens known to regulate epithelial/mesenchymal interactions during embryonic development. In addition to its pivotal role in embryogenesis, the Hh signaling pathway may be recapitulated in post-natal life in a number of physiological and pathological conditions, including ischemia. This review highlights the involvement of Hh signaling in ischemic tissue regeneration and angiogenesis, with particular attention to the heart, the brain, and the skeletal muscle. Updated information on the potential role of the Hh pathway as a therapeutic target in the ischemic condition is also presented.

scholarly journals Membrane potential regulates Hedgehog signaling and compartment boundary maintenance in the Drosophila wing disc

2020 ◽  
Author(s):  
Maya Emmons-Bell ◽  
Riku Yasutomi ◽  
Iswar K. Hariharan
Keyword(s):  
Membrane Potential ◽  
Hedgehog Signaling ◽  
Membrane Depolarization ◽  
Wing Disc ◽  
Anterior Compartment ◽  
Drosophila Wing ◽  
Compartment Boundary ◽  
Boundary Maintenance ◽  
Elevated Expression ◽  
Hh Signaling

AbstractThe Drosophila wing imaginal disc is composed of two lineage-restricted populations of cells separated by a smooth boundary. Hedgehog (Hh) from posterior cells activates a signaling pathway in anterior cells near the boundary which is necessary for boundary maintenance. Here, we show that membrane potential is patterned in the wing disc. Anterior cells near the boundary, where Hh signaling is most active, are more depolarized than posterior cells across the boundary. Elevated expression of the ENaC channel Ripped Pocket (Rpk), observed in these anterior cells, requires Hh. Antagonizing Rpk reduces depolarization and disrupts the compartment boundary. Using genetic and optogenetic manipulations, we show that membrane depolarization promotes membrane localization of Smoothened and augments Hh signaling. Thus, membrane depolarization and Hh-dependent signaling mutually reinforce each other in this region. Finally, clones of depolarized cells survive preferentially in the anterior compartment and clones of hyperpolarized cells survive preferentially in the posterior compartment.

scholarly journals Understanding the Hedgehog Signaling Pathway in Acute Myeloid Leukemia Stem Cells: A Necessary Step toward a Cure

Biology ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 255
Author(s):  
Daniel Lainez-González ◽  
Juana Serrano-López ◽  
Juan Manuel Alonso-Domínguez
Keyword(s):  
Stem Cells ◽  
Acute Myeloid Leukemia ◽  
Signaling Pathway ◽  
Myeloid Leukemia ◽  
Hedgehog Signaling ◽  
Hedgehog Signaling Pathway ◽  
Leukemic Stem Cells ◽  
Hh Signaling ◽  
Acute Myeloid

A better understanding of how signaling pathways govern cell fate is fundamental to advances in cancer development and treatment. The initialization of different tumors and their maintenance are caused by the deregulation of different signaling pathways and cancer stem cell maintenance. Quiescent stem cells are resistant to conventional chemotherapeutic treatments and, consequently, are responsible for disease relapse. In this review we focus on the conserved Hedgehog (Hh) signaling pathway which is involved in regulating the cell cycle of hematopoietic and leukemic stem cells. Thus, we examine the role of the Hh signaling pathway in normal and leukemic stem cells and dissect its role in acute myeloid leukemia. We explain not only the connection between illness and the signaling pathway but also evaluate innovative therapeutic approaches that could affect the outcome of patients with acute myeloid leukemia. We found that many aspects of the Hedgehog signaling pathway remain unknown. The role of Hh has only been proven in embryo and hematopoietic stem cell development. Further research is needed to elucidate the role of GLI transcription factors for therapeutic targeting. Glasdegib, an SMO inhibitor, has shown clinical activity in acute myeloid leukemia; however, its mechanism of action is not clear.

scholarly journals The Role of Sonic Hedgehog-Gli2 Pathway in the Masculinization of External Genitalia

Endocrinology ◽  
2011 ◽  
Vol 152 (7) ◽  
pp. 2894-2903 ◽  
Author(s):  
Shinichi Miyagawa ◽  
Daisuke Matsumaru ◽  
Aki Murashima ◽  
Akiko Omori ◽  
Yoshihiko Satoh ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Sonic Hedgehog ◽  
Hedgehog Signaling ◽  
External Genitalia ◽  
Sexually Dimorphic ◽  
Hedgehog Signaling Pathway ◽  
Initial Development ◽  
Urethral Plate ◽  
Male External Genitalia

During embryogenesis, sexually dimorphic organogenesis is achieved by hormones produced in the gonad. The external genitalia develop from a single primordium, the genital tubercle, and their masculinization processes depend on the androgen signaling. In addition to such hormonal signaling, the involvement of nongonadal and locally produced masculinization factors has been unclear. To elucidate the mechanisms of the sexually dimorphic development of the external genitalia, series of conditional mutant mouse analyses were performed using several mutant alleles, particularly focusing on the role of hedgehog signaling pathway in this manuscript. We demonstrate that hedgehog pathway is indispensable for the establishment of male external genitalia characteristics. Sonic hedgehog is expressed in the urethral plate epithelium, and its signal is mediated through glioblastoma 2 (Gli2) in the mesenchyme. The expression level of the sexually dimorphic genes is decreased in the glioblastoma 2 mutant embryos, suggesting that hedgehog signal is likely to facilitate the masculinization processes by affecting the androgen responsiveness. In addition, a conditional mutation of Sonic hedgehog at the sexual differentiation stage leads to abnormal male external genitalia development. The current study identified hedgehog signaling pathway as a key factor not only for initial development but also for sexually dimorphic development of the external genitalia in coordination with androgen signaling.

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.

Positional signaling by hedgehog in Drosophila imaginal disc development

Development ◽  
1995 ◽  
Vol 121 (1) ◽  
pp. 1-10 ◽  
Author(s):  
A.L. Felsenfeld ◽  
J.A. Kennison
Keyword(s):  
Hedgehog Signaling ◽  
Imaginal Disc ◽  
Ectopic Expression ◽  
Posterior Compartment ◽  
Anterior Compartment ◽  
Segment Polarity ◽  
Wing Structures ◽  
Wing Discs ◽  
Segment Polarity Gene ◽  
Polarity Gene

We describe a dominant gain-of-function allele of the segment polarity gene hedgehog. This mutation causes ectopic expression of hedgehog mRNA in the anterior compartment of wing discs, leading to overgrowth of tissue in the anterior of the wing and partial duplication of distal wing structures. The posterior compartment of the wing is unaffected. Other imaginal derivatives are affected, resulting in duplications of legs and antennae and malformations of eyes. In mutant imaginal wing discs, expression of the decapentaplegic gene, which is implicated in the hedgehog signaling pathway, is also perturbed. The results suggest that hedgehog protein acts in the wing as a signal to instruct neighboring cells to adopt fates appropriate to the region of the wing just anterior to the compartmental boundary.

Nubbin encodes a POU-domain protein required for proximal-distal patterning in the Drosophila wing

Development ◽  
1995 ◽  
Vol 121 (2) ◽  
pp. 589-599 ◽  
Author(s):  
M. Ng ◽  
F.J. Diaz-Benjumea ◽  
S.M. Cohen
Keyword(s):  
Growth Control ◽  
Normal Growth ◽  
Control Center ◽  
Genetic Mosaics ◽  
Drosophila Wing ◽  
Pou Domain ◽  
Compartment Boundary ◽  
Wing Structures ◽  
Wing Imaginal Discs ◽  
Anterior Posterior

The nubbin gene is required for normal growth and patterning of the wing in Drosophila. We report here that nubbin encodes a member of the POU family of transcription factors. Regulatory mutants which selectively remove nubbin expression from wing imaginal discs lead to loss of wing structures. Although nubbin is expressed throughout the wing primordium, analysis of genetic mosaics suggests a localized requirement for nubbin activity in the wing hinge. These observations suggest the existence of a novel proximal-distal growth control center in the wing hinge, which is required in addition to the well characterized anterior-posterior and dorsal-ventral compartment boundary organizing centers.

Sign in / Sign up

Export Citation Format

Share Document