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

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.

Development ◽  
1998 ◽  
Vol 125 (15) ◽  
pp. 2951-2962 ◽  
Author(s):  
T. Klein ◽  
A.M. Arias

The Notch signalling pathway plays an important role during the development of the wing primordium, especially of the wing blade and margin. In these processes, the activity of Notch is controlled by the activity of the dorsal specific nuclear protein Apterous, which regulates the expression of the Notch ligand, Serrate, and the Fringe signalling molecule. The other Notch ligand, Delta, also plays a role in the development and patterning of the wing. It has been proposed that Fringe modulates the ability of Serrate and Delta to signal through Notch and thereby restricts Notch signalling to the dorsoventral boundary of the developing wing blade. Here we report the results of experiments aimed at establishing the relationships between Fringe, Serrate and Delta during wing development. We find that Serrate is not required for the initiation of wing development but rather for the expansion and early patterning of the wing primordium. We provide evidence that, at the onset of wing development, Delta is under the control of apterous and might be the Notch ligand in this process. In addition, we find that Fringe function requires Su(H). Our results suggest that Notch signalling during wing development relies on careful balances between positive and dominant negative interactions between Notch ligands, some of which are mediated by Fringe.


Genetics ◽  
1997 ◽  
Vol 147 (3) ◽  
pp. 1203-1212 ◽  
Author(s):  
Katerina Nestoras ◽  
Helena Lee ◽  
Jym Mohler

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.


Author(s):  
Marina Campione ◽  
Amelia Aranega ◽  
Diego Franco

Dextral looping is a complex process which progresses concomitantly with cardiac chamber differentiation and ultimately leads to the final alignment of the cardiac regions. Generation of cardiac asymmetry is crucial to ensure the proper form and consequent function of the heart and thus is a highly regulated process. Molecular signals originate long before morphological asymmetry and therefore can direct it; a complex regulatory network has been characterized which invariably converges on the Tgf-β‎ signalling molecule Nodal and its downstream target, the homeobox transcription factor Pitx2. We review current data regarding the cellular and molecular bases of cardiac looping and laterality, and describe current understaning of the role of Nodal and Pitx2. The morphogenetic role of the Pitx2 gene and its modulation of transcription and function, which have recently linked laterality to atrial fibrillation, are emphasized.


Development ◽  
2002 ◽  
Vol 129 (17) ◽  
pp. 3995-4004
Author(s):  
David del Álamo Rodríguez ◽  
Javier Terriente ◽  
Máximo I. Galindo ◽  
Juan Pablo Couso ◽  
Fernando J. Díaz-Benjumea

The Drosophila gene wingless encodes a secreted signalling molecule that is required for many patterning events in both embryonic and postembryonic development. In the wing wingless is expressed in a complex and dynamic pattern that is controlled by several different mechanisms. These involve the Hedgehog and Notch pathways and the nuclear proteins Pannier and U-shaped. In this report, we analyse the mechanisms that drive wingless expression in the wing hinge. We present evidence that wingless is initially activated by a secreted signal that requires the genes vestigial, rotund and nubbin. Later in development, wingless expression in the wing hinge is maintained by a different mechanism, which involves an autoregulatory loop and requires the genes homothorax and rotund. We discuss the role of wingless in patterning the wing hinge.


Author(s):  
Maria L Dias ◽  
Karen M O'Connor ◽  
Eugene Dempsey ◽  
Ken D. O'Halloran ◽  
Fiona Brigid McDonald

Toll-like receptors (TLRs) are crucial transmembrane receptors that form part of the innate immune response. They play a role in the recognition of various microorganisms and their elimination from the host. TLRs have been proposed as vital immunomodulators in the regulation of multiple neonatal stressors that extend beyond infection such as oxidative stress and pain. The immune system is immature at birth and takes some time to become fully established. As such, babies are especially vulnerable to sepsis at this early stage of life. Findings suggest a gestational age-dependent increase in TLR expression. TLRs engage with accessory and adaptor proteins to facilitate recognition of pathogens and their activation of the receptor. TLRs are generally upregulated during infection and promote the transcription and release of proinflammatory cytokines. Several studies report that TLRs are epigenetically modulated by chromatin changes and promoter methylation upon bacterial infection which have long-term influences on immune responses. TLR activation is reported to modulate cardiorespiratory responses during infection and may play a key role in driving homeostatic instability observed during sepsis. Although complex, TLR signalling and downstream pathways are potential therapeutic targets in the treatment of neonatal diseases. By reviewing the expression and function of key toll-like receptors, we aim to provide an important framework to understand the functional role of these receptors in response to stress and infection in premature infants.


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 ◽  
1995 ◽  
Vol 121 (10) ◽  
pp. 3359-3369 ◽  
Author(s):  
T. Tabata ◽  
C. Schwartz ◽  
E. Gustavson ◽  
Z. Ali ◽  
T.B. Kornberg

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.


2014 ◽  
Vol 42 (1) ◽  
pp. 42-46 ◽  
Author(s):  
Rachel E. Martin ◽  
Zhenbo Cao ◽  
Neil J. Bulleid

Hydrogen peroxide (H2O2) can act as a signalling molecule affecting the cell cycle as well as contributing towards the oxidative stress response. The primary target of this molecule is oxidation-sensitive cysteine residues in proteins such as protein tyrosine phosphatases. The cell has robust mechanisms to remove H2O2 that need to be regulated for H2O2 to react with and modify protein thiols. In particular, the family of peroxiredoxins are capable of the rapid removal of even trace amounts of this molecule. It has been suggested that the inactivation of peroxiredoxins by hyperoxidation may allow H2O2 levels to increase in cells and thereby modify critical thiol groups in proteins. We have been studying how the H2O2 produced during disulfide formation in the ER (endoplasmic reticulum) is metabolized and have shown that ER-resident peroxiredoxin IV not only can remove H2O2, but also contributes to de novo disulfide formation. In the present article, we review recent data on the structure and function of this enzyme as well as its sensitivity to hyperoxidation.


eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Stefan Harmansa ◽  
Ilaria Alborelli ◽  
Dimitri Bieli ◽  
Emmanuel Caussinus ◽  
Markus Affolter

The role of protein localization along the apical-basal axis of polarized cells is difficult to investigate in vivo, partially due to lack of suitable tools. Here, we present the GrabFP system, a collection of four nanobody-based GFP-traps that localize to defined positions along the apical-basal axis. We show that the localization preference of the GrabFP traps can impose a novel localization on GFP-tagged target proteins and results in their controlled mislocalization. These new tools were used to mislocalize transmembrane and cytoplasmic GFP fusion proteins in the Drosophila wing disc epithelium and to investigate the effect of protein mislocalization. Furthermore, we used the GrabFP system as a tool to study the extracellular dispersal of the Decapentaplegic (Dpp) protein and show that the Dpp gradient forming in the lateral plane of the Drosophila wing disc epithelium is essential for patterning of the wing imaginal disc.


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