Growth and cell competition in Drosophila

Development ◽  
1981 ◽  
Vol 65 (Supplement) ◽  
pp. 77-88
Author(s):  
Pat Simpson
Keyword(s):  
Imaginal Discs ◽  
Wing Disc ◽  
Cell Competition ◽  
Imaginal Wing Disc ◽  
Adult Abdomen

The process of cell competition, whereby slowly dividing Minute cells are eliminated by faster-growing Minute+ cells in mosaic compartments of the imaginal wing disc, is discussed. Evidence is presented suggesting that after completion of growth of the imaginal discs, Minute+ cells no longer continue overgrowing and eliminating the Minute cells. The process of competition thus appears to be restricted to discs that are actively growing. No cell competition can be detected in the histoblast cells that give rise to the adult abdomen. This observation, however, has been interpreted to be the result of an extremely long perdurance effect for the Minute+ product in these cells.

Tumorigenesis and cell competition in Drosophila in the absence of polyhomeotic function

2021 ◽  
Vol 118 (45) ◽  
pp. e2110062118
Author(s):  
Izarne Medina ◽  
Manuel Calleja ◽  
Ginés Morata
Keyword(s):  
Tumor Cells ◽  
Imaginal Discs ◽  
Wing Disc ◽  
Tissue Cell ◽  
Animal Tissues ◽  
Cell Competition ◽  
Homeostatic Process ◽  
Mutant Cells

Cell competition is a homeostatic process that eliminates by apoptosis unfit or undesirable cells from animal tissues, including tumor cells that appear during the life of the organism. In Drosophila there is evidence that many types of oncogenic cells are eliminated by cell competition. One exception is cells mutant for polyhomeotic (ph), a member of the Polycomb family of genes; most of the isolated mutant ph clones survive and develop tumorous overgrowths in imaginal discs. To characterize the tumorigenic effect of the lack of ph, we first studied the growth of different regions of the wing disc deficient in ph activity and found that the effect is restricted to the proximal appendage. Moreover, we found that ph-deficient tissue is partially refractory to apoptosis. Second, we analyzed the behavior of clones lacking ph function and found that many suffer cell competition but are not completely eliminated. Unexpectedly, we found that nonmutant cells also undergo cell competition when surrounded by ph-deficient cells, indicating that within the same tissue cell competition may operate in opposite directions. We suggest two reasons for the incompleteness of cell competition in ph mutant cells: 1) These cells are partially refractory to apoptosis, and 2) the loss of ph function alters the identity of imaginal cells and subsequently their cell affinities. It compromises the winner/loser interaction, a prerequisite for cell competition.

Dpp signalling is a key effector of the wing-body wall subdivision of theDrosophilamesothorax

Development ◽  
2002 ◽  
Vol 129 (16) ◽  
pp. 3815-3823 ◽  
Author(s):  
Florencia Cavodeassi ◽  
Isabel Rodríguez ◽  
Juan Modolell
Keyword(s):  
Body Wall ◽  
Larval Instar ◽  
Proximal Part ◽  
Distal Region ◽  
Wing Disc ◽  
Signalling Pathway ◽  
Wing Development ◽  
C Cells ◽  
Imaginal Wing Disc ◽  
Anterior Posterior

During development, the imaginal wing disc of Drosophila is subdivided along the proximal-distal axis into different territories that will give rise to body wall (notum and mesothoracic pleura) and appendage (wing hinge and wing blade). Expression of the Iroquois complex (Iro-C) homeobox genes in the most proximal part of the disc defines the notum, since Iro-C– cells within this territory acquire the identity of the adjacent distal region, the wing hinge. Here we analyze how the expression of Iro-C is confined to the notum territory. Neither Wingless signalling, which is essential for wing development, nor Vein-dependent EGFR signalling, which is needed to activate Iro-C, appear to delimit Iro-C expression. We show that a main effector of this confinement is the TGFβ homolog Decapentaplegic (Dpp), a molecule known to pattern the disc along its anterior-posterior axis. At early second larval instar, the Dpp signalling pathway functions only in the wing and hinge territories, represses Iro-C and confines its expression to the notum territory. Later, Dpp becomes expressed in the most proximal part of the notum and turns off Iro-C in this region. This downregulation is associated with the subdivision of the notum into medial and lateral regions.

scholarly journals Transvection in the Drosophila Ultrabithorax gene: a Cbx1 mutant allele induces ectopic expression of a normal allele in trans.

Genetics ◽  
1990 ◽  
Vol 126 (1) ◽  
pp. 177-184 ◽  
Author(s):  
J E Castelli-Gair ◽  
J L Micol ◽  
A García-Bellido
Keyword(s):  
Double Mutant ◽  
Ectopic Expression ◽  
Imaginal Discs ◽  
Wing Disc ◽  
Loss Of Function ◽  
Normal Allele ◽  
Single Mutant ◽  
Adult Wing ◽  
Disc Cells ◽  
In Cis

Abstract In wild-type Drosophila melanogaster larvae, the Ultrabithorax (Ubx) gene is expressed in the haltere imaginal discs but not in the majority of cells of the wing imaginal discs. Ectopic expression of the Ubx gene in wing discs can be elicited by the presence of Contrabithorax (Cbx) gain-of-function alleles of the Ubx gene or by loss-of-function mutations in Polycomb (Pc) or in other trans-regulatory genes which behave as repressors of Ubx gene activity. Several Ubx loss-of-function alleles cause the absence of detectable Ubx proteins (UBX) or the presence of truncated UBX lacking the homeodomain. We have compared adult wing phenotypes with larval wing disc UBX patterns in genotypes involving double mutant chromosomes carrying in cis one of those Ubx mutations and the Cbx1 mutation. We show that such double mutant genes are (1) active in the same cells in which the single mutant Cbx1 is expressed, although they are unable to yield functional proteins, and (2) able to induce ectopic expression of a normal homologous Ubx allele in a part of the cells in which the single mutant Cbx1 is active. That induction is conditional upon pairing of the homologous chromosomes (the phenomenon known as transvection), and it is not mediated by UBX. Depletion of Pc gene products by Pc3 mutation strongly enhances the induction phenomenon, as shown by (1) the increase of the number of wing disc cells in which induction of the homologous allele is detectable, and (2) the induction of not only a paired normal allele but also an unpaired one.

scholarly journals Transgressions of compartment boundaries and cell reprogramming during regeneration in Drosophila

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Salvador C Herrera ◽  
Ginés Morata
Keyword(s):  
Control Mechanism ◽  
Imaginal Discs ◽  
Wing Disc ◽  
Cell Reprogramming ◽  
Developmental Genes ◽  
Jnk Pathway ◽  
Cubitus Interruptus ◽  
Developmental Context ◽  
Epigenetic Control ◽  
Developmental Reprogramming

Animals have developed mechanisms to reconstruct lost or damaged tissues. To regenerate those tissues the cells implicated have to undergo developmental reprogramming. The imaginal discs of Drosophila are subdivided into distinct compartments, which derive from different genetic programs. This feature makes them a convenient system to study reprogramming during regeneration. We find that massive damage inflicted to the posterior or the dorsal compartment of the wing disc causes a transient breakdown of compartment boundaries, which are quickly reconstructed. The cells involved in the reconstruction often modify their original identity, visualized by changes in the expression of developmental genes like engrailed or cubitus interruptus. This reprogramming is mediated by up regulation of the JNK pathway and transient debilitation of the epigenetic control mechanism. Our results also show that the local developmental context plays a role in the acquisition of new cell identities: cells expressing engrailed induce engrailed expression in neighbor cells.

Connecting Hh, Dpp and EGF signalling in patterning of theDrosophilawing; the pivotal role ofcollier/knotin the AP organiser

Development ◽  
2002 ◽  
Vol 129 (18) ◽  
pp. 4261-4269 ◽  
Author(s):  
Michèle Crozatier ◽  
Bruno Glise ◽  
Alain Vincent
Keyword(s):  
Cell Proliferation ◽  
Central Region ◽  
Wing Disc ◽  
Signalling Pathways ◽  
Wild Type ◽  
Drosophila Wing ◽  
Egfr Ligand ◽  
Imaginal Wing Disc ◽  
Primary Determinant ◽  
Dose Dependent

Hedgehog (Hh) signalling from posterior (P) to anterior (A) cells is the primary determinant of AP polarity in the limb field in insects and vertebrates. Hh acts in part by inducing expression of Decapentaplegic (Dpp), but how Hh and Dpp together pattern the central region of the Drosophila wing remains largely unknown. We have re-examined the role played by Collier (Col), a dose-dependent Hh target activated in cells along the AP boundary, the AP organiser in the imaginal wing disc. We found that col mutant wings are smaller than wild type and lack L4 vein, in addition to missing the L3-L4 intervein and mis-positioning of the anterior L3 vein. We link these phenotypes to col requirement for the local upregulation of both emc and N, two genes involved in the control of cell proliferation, the EGFR ligand Vein and the intervein determination gene blistered. We further show that attenuation of Dpp signalling in the AP organiser is also col dependent and, in conjunction with Vein upregulation, required for formation of L4 vein. A model recapitulating the molecular interplay between the Hh, Dpp and EGF signalling pathways in the wing AP organiser is presented.

Lineage-tracing cells born in different domains along the PD axis of the developing Drosophila leg

Development ◽  
1999 ◽  
Vol 126 (17) ◽  
pp. 3823-3830 ◽  
Author(s):  
K. Weigmann ◽  
S.M. Cohen
Keyword(s):  
Cell Fate ◽  
Imaginal Discs ◽  
Wing Disc ◽  
Lineage Tracing ◽  
Ligand Concentration ◽  
Signaling Proteins ◽  
Cell Fate Specification ◽  
Morphogen Gradients ◽  
Fate Specification ◽  
Lower Ligand

Patterning of the developing limbs by the secreted signaling proteins Wingless, Hedgehog and Dpp takes place while the imaginal discs are growing rapidly. Cells born in regions of high ligand concentration may be displaced through growth to regions of lower ligand concentration. We have used a novel lineage-tagging method to address the reversibility of cell fate specification by morphogen gradients. We find that responses to Hedgehog and Dpp in the wing disc are readily reversible. In the leg, we find that cells readily adopt more distal fates, but do not normally shift from distal to proximal fate. However, they can do so if given a growth advantage. These results indicate that cell fate specification by morphogen gradients remains largely reversible while the imaginal discs grow. In other systems, where growth and patterning are uncoupled, nonreversible specification events or ‘ratchet’ effects may be of functional significance.

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