Establishing primordia in the Drosophila eye-antennal imaginal disc: the roles of decapentaplegic, wingless and hedgehog

Development ◽  
1997 ◽  
Vol 124 (23) ◽  
pp. 4793-4800 ◽  
Author(s):  
J. Royet ◽  
R. Finkelstein

The eye-antennal imaginal discs of Drosophila melanogaster form the head capsule of the adult fly. Unlike the limb primordia, each eye-antennal disc gives rise to morphologically and functionally distinct structures. As a result, these discs provide an excellent model system for determining how the fates of primordia are specified during development. In this study, we investigated how the adjacent primordia of the compound eye and dorsal head vertex are specified. We show that the genes wingless (wg) and orthodenticle (otd) are expressed throughout the entire second instar eye-antennal disc, conferring a default fate of dorsal vertex cuticle. Activation of decapentaplegic (dpp) expression in the posterior eye disc eliminates wg and otd expression, thereby permitting eye differentiation. We also demonstrate that otd is activated by wg in the vertex primordium. Finally, we show that early activation of dpp depends on hedgehog (hh) expression in the eye anlage prior to morphogenetic furrow formation.

Development ◽  
1987 ◽  
Vol 100 (2) ◽  
pp. 261-269
Author(s):  
D.J. Andrew

In specific genetic backgrounds, a mutation in the tuh-3 gene results in the homeotic transformation of head structures to either leg disc derivatives or structures normally found in the extreme posterior end of wild-type animals. The origins of the homeotic structures were mapped to defined positions in the eye-antennal imaginal disc by transplanting abnormal regions of discs isolated from tuh-3 mutants into host mwh;e4 larvae. These metamorphosed implants were removed and differentiated structures were identified. Of 211 successfully recovered implants, 157 gave rise to homeotic tissue: abdominal tergite, male or female external genitalia and/or leg tissue. Transformations to abdominal tergite occurred primarily in cells taken from the eye region of the compound disc. Male and female genitalia arose most often in implants taken from the antennal portion of the disc, although some tissue taken from the lateral region of the eye disc also gave rise to external genitalia. Leg structures came exclusively from implants from the antennal region of the imaginal disc. These results suggest that cells from within specific regions of the eye-antennal compound disc are constrained in their developmental potential. An obvious constraint observed with this mutation is a dorsal/ventral one: Cells from the eye disc, a dorsal structure, primarily gave rise to other dorsal structures, abdominal tergite tissue. Cells from the antennal disc, a ventrally derived structure, primarily gave rise to other ventral structures including genital tissue and distal leg.


Development ◽  
1996 ◽  
Vol 122 (6) ◽  
pp. 1849-1858 ◽  
Author(s):  
J. Royet ◽  
R. Finkelstein

The adult head capsule of Drosophila forms primarily from the eye-antennal imaginal discs. Here, we demonstrate that the head primordium is patterned differently from the discs which give rise to the appendages. We show that the segment polarity genes hedgehog and wingless specify the identities of specific regions of the head capsule. During eye-antennal disc development, hedgehog and wingless expression initially overlap, but subsequently segregate. This regional segregation is critical to head specification and is regulated by the orthodenticle homeobox gene. We also show that orthodenticle is a candidate hedgehog target gene during early eye-antennal disc development.


Development ◽  
1997 ◽  
Vol 124 (17) ◽  
pp. 3233-3240 ◽  
Author(s):  
D.I. Strutt ◽  
M. Mlodzik

Pattern formation in the eye imaginal disc of Drosophila occurs in a wave that moves from posterior to anterior. The anterior edge of this wave is marked by a contracted band of cells known as the morphogenetic furrow, behind which photoreceptors differentiate. The movement of the furrow is dependent upon the secretion of the signalling protein Hedgehog (Hh) by more posterior cells, and it has been suggested that Hh acts as an inductive signal to induce cells to enter a furrow fate and begin differentiation. To further define the role of Hh in this process, we have analysed clones of cells lacking the function of the smoothened (smo) gene, which is required for transduction of the Hh signal and allows the investigation of the autonomous requirement for hh signalling. These experiments demonstrate that the function of hh in furrow progression is indirect. Cells that cannot receive/transduce the Hh signal are still capable of entering a furrow fate and differentiating normally. However, hh is required to promote furrow progression and regulate its rate of movement across the disc, since the furrow is significantly delayed in smo clones.


1992 ◽  
Vol 12 (11) ◽  
pp. 5111-5122
Author(s):  
M Agnel ◽  
L Röder ◽  
C Vola ◽  
R Griffin-Shea

The rotund (rn) locus of Drosophila melanogaster at cytogenetic position 84D3,4 has been isolated and cloned on the basis of the mutant phenotype: an absence of structures in the subdistal regions of the appendages. The shortened appendages are the consequence of a localized cell death in the imaginal discs, precursors of the adult appendages. Physical characterization of the rn locus has demonstrated that it is relatively large, occupying a minimum of 50 kb. There are two major transcripts of 1.7 kb (m1.7) and 5.3 kb (m5.3). We present here the sequence analysis of m1.7 and its putative product, rnprot1.7, and show that rnprot1.7 is similar to the product of the human n-chimaerin gene, which is expressed in brain and testes. Recently, the GAP activity of n-chimaerin was demonstrated and shown to be specific for the Rac subfamily of the Ras oncoproteins. The Rac proteins have been implicated in the regulation of secretory processes. In addition to being expressed in the imaginal discs, the m1.7 racGAP transcript was detected in developmentally specific germ line cells of the testes, the primary spermatocytes.


1992 ◽  
Vol 12 (11) ◽  
pp. 5111-5122 ◽  
Author(s):  
M Agnel ◽  
L Röder ◽  
C Vola ◽  
R Griffin-Shea

The rotund (rn) locus of Drosophila melanogaster at cytogenetic position 84D3,4 has been isolated and cloned on the basis of the mutant phenotype: an absence of structures in the subdistal regions of the appendages. The shortened appendages are the consequence of a localized cell death in the imaginal discs, precursors of the adult appendages. Physical characterization of the rn locus has demonstrated that it is relatively large, occupying a minimum of 50 kb. There are two major transcripts of 1.7 kb (m1.7) and 5.3 kb (m5.3). We present here the sequence analysis of m1.7 and its putative product, rnprot1.7, and show that rnprot1.7 is similar to the product of the human n-chimaerin gene, which is expressed in brain and testes. Recently, the GAP activity of n-chimaerin was demonstrated and shown to be specific for the Rac subfamily of the Ras oncoproteins. The Rac proteins have been implicated in the regulation of secretory processes. In addition to being expressed in the imaginal discs, the m1.7 racGAP transcript was detected in developmentally specific germ line cells of the testes, the primary spermatocytes.


2020 ◽  
Vol 21 (11) ◽  
pp. 4086
Author(s):  
Tuan L. A. Pham ◽  
Tran Duy Binh ◽  
Guanchen Liu ◽  
Thanh Q. C. Nguyen ◽  
Yen D. H. Nguyen ◽  
...  

Serotonin transporter (SerT) in the brain is an important neurotransmitter transporter involved in mental health. However, its role in peripheral organs is poorly understood. In this study, we investigated the function of SerT in the development of the compound eye in Drosophila melanogaster. We found that SerT knockdown led to excessive cell death and an increased number of cells in S-phase in the posterior eye imaginal disc. Furthermore, the knockdown of SerT in the eye disc suppressed the activation of Akt, and the introduction of PI3K effectively rescued this phenotype. These results suggested that SerT plays a role in the healthy eye development of D. melanogaster by controlling cell death through the regulation of the PI3K/Akt pathway.


2015 ◽  
Author(s):  
Jacob S. Jaszczak ◽  
Jacob B. Wolpe ◽  
Rajan Bhandari ◽  
Rebecca G. Jaszczak ◽  
Adrian Halme

Damage to Drosophila melanogaster imaginal discs activates a regeneration checkpoint that 1) extends larval development and 2) coordinates the regeneration of the damaged disc with the growth of undamaged discs. These two systemic responses to damage are both mediated by Dilp8, a member of the insulin/IGF/relaxin family of peptide hormones, which is released by regenerating imaginal discs. Growth coordination between regenerating and undamaged imaginal discs is dependent on Dilp8 activation of NOS in the prothoracic gland (PG), which slows the growth of undamaged discs by limiting ecdysone synthesis. Here we demonstrate that the Drosophila relaxin receptor homologue Lgr3, a leucine-rich repeat-containing G-protein coupled receptor, is required for Dilp8-dependent growth coordination and developmental delay during the regeneration checkpoint. Lgr3 regulates these responses to damage via distinct mechanisms in different tissues. Using tissue-specific RNAi disruption of Lgr3 expression, we show that Lgr3 functions in the PG upstream of nitric oxide synthase (NOS), and is necessary for NOS activation and growth coordination during the regeneration checkpoint. When Lgr3 is depleted from neurons, imaginal disc damage no longer produces either developmental delay or growth inhibition. To reconcile these discrete tissue requirements for Lgr3 during regenerative growth coordination, we demonstrate that Lgr3 activity in the both the CNS and PG is necessary for NOS activation in the PG following damage. Together, these results identify new roles for a relaxin receptor in mediating damage signaling to regulate growth and developmental timing.


Genetics ◽  
1998 ◽  
Vol 150 (1) ◽  
pp. 189-198
Author(s):  
Anthony Percival-Smith ◽  
Danielle J Hayden

Abstract Sex Combs Reduced (SCR) activity is proposed to be required cell nonautonomously for determination of tarsus identity, and Extradenticle (EXD) activity is required cell autonomously for determination of arista identity. Using the ability of Proboscipedia to inhibit the SCR activity required for determination of tarsus identity, we found that loss-of-EXD activity is epistatic to loss-of-SCR activity in tarsus vs. arista determination. This suggests that in the sequence leading to arista determination SCR activity is OFF while EXD activity is ON, and in the sequence leading to tarsus determination SCR activity is ON, which turns EXD activity OFF. Immunolocalization of EXD in early third-instar larval imaginal discs reveals that EXD is localized in the nuclei of antennal imaginal disc cells and localized in the cytoplasm of distal imaginal leg disc cells. We propose that EXD localized to the nucleus suppresses tarsus determination and activates arista determination. We further propose that in the mesodermal adepithelial cells of the leg imaginal discs, SCR is required for the synthesis of a tarsus-inducer that when secreted acts on the ectoderm cells inhibiting nuclear accumulation of EXD, such that tarsus determination is no longer suppressed and arista determination is no longer activated.


Development ◽  
1976 ◽  
Vol 36 (1) ◽  
pp. 109-125
Author(s):  
Robert Ransom

An account of the patterns of clones induced on the head cuticle of Drosophila melanogaster is given. The system was studied using mitotic recombination, induced by X-rays at certain developmental stages. In agreement with the findings of a computer model devised to simulate growth in the head imaginal disc, cuticle clones are found to have a characteristic pattern, weeping round the central, eye-forming part of the disc. The similarity between model and experiment suggests the validity of the model assumption. It is also shown that cuticle clones are not smaller in the posterior of the head, when induced at the developmental stages studied: this is in contrast to clones in the compound eye, where posterior clones are smaller thananterior ones.


Development ◽  
1993 ◽  
Vol 118 (4) ◽  
pp. 1107-1121 ◽  
Author(s):  
M. Meise ◽  
W. Janning

We have analyzed the cell lineage of larval and imaginal cells in the thoracic ectoderm of the early embryo of Drosophila melanogaster, by homotopic transplantation of single cells in the region of 50–60% egg length. Single cells were isolated prior to transplantation in an in vitro solution. The donors were ‘enhancer-trap’ lines in which the nuclei of all larval and imaginal cells exhibit a uniformly intense expression of the lacZ gene of E. coli. The transplantations were carried out from the blastoderm to the early gastrula stage, as a rule immediately after the onset of gastrulation (stage 6). It was found that at this time the cells of the thoracic ectoderm are not yet committed to form larval or imaginal structures, as indicated by the presence of clones overlapping all structures formed by the thoracic ectoderm, i.e. the nervous system, the larval epidermis, the tracheae and the imaginal discs. The average size of pure epidermal clones was five cells. In clones overlapping either other larval tissues or imaginal discs, the average number of epidermal cells was between three and four. The mean relative clone size was 1/5 of the size of the total structure for leg imaginal discs and 1/7 for the wing imaginal disc. We therefore infer that the precursors for the leg discs and wing disc on one side together number 22 cells in the blastoderm or early gastrula stage. These cells eventually give rise not only to precursors of the imaginal discs but usually also to larval epidermal and nervous-system cells, because most of the imaginal disc clones (80%) overlap larval tissue. The transplantations were not precisely homotopic; the fact that up to 10 cells were removed from the donor essentially rules out exact homotopy between donor and host sites, because a segment anlage is only about three cells wide. Nevertheless, the clones developed completely normal tissue together with the recipient cells. Although the clones have the capacity to extend over different ectodermal tissues and can include both imaginal discs in a given segment, no clones were found that clearly crossed larval or imaginal segment boundaries. We propose a model in which the segregation of the cells that are to differentiate into the imaginal tissues does not occur until the second postblastodermal mitosis


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