hedgehog, wingless and orthodenticle specify adult head development in Drosophila

Development ◽  
1996 ◽  
Vol 122 (6) ◽  
pp. 1849-1858 ◽  
Author(s):  
J. Royet ◽  
R. Finkelstein
Keyword(s):  
Target Gene ◽  
Homeobox Gene ◽  
Head Capsule ◽  
Imaginal Discs ◽  
Segment Polarity Genes ◽  
Head Development ◽  
Segment Polarity ◽  
Adult Head ◽  
Antennal Disc

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.

A positive role for Patched-Smoothened signaling in promoting cell proliferation during normal head development in Drosophila

Development ◽  
2002 ◽  
Vol 129 (8) ◽  
pp. 1839-1847 ◽  
Author(s):  
Baragur V. Shyamala ◽  
Krishna Moorthi Bhat
Keyword(s):  
Cell Proliferation ◽  
Head Capsule ◽  
Type I ◽  
Positive Role ◽  
Promote Cell Proliferation ◽  
Head Development ◽  
Adult Head ◽  
G Protein Coupled ◽  
Antennal Disc ◽  
Normal Head

The transmembrane receptor Patched regulates several developmental processes in both invertebrates and vertebrates. In vertebrates, Patched also acts as a tumor suppressor. The Patched pathway normally operates by negatively regulating Smoothened, a G-protein-coupled receptor; binding of Hedgehog ligand to Patched relieves this negative interaction and allows signaling by Smoothened. We show that Ptc regulates Drosophila head development by promoting cell proliferation in the eye-antennal disc. During head morphogenesis, Patched positively interacts with Smoothened, which leads to the activation of Activin type I receptor Baboon and stimulation of cell proliferation in the eye-antennal disc. Thus, loss of Ptc or Smoothened activity affects cell proliferation in the eye-antennal disc and results in adult head capsule defects. Similarly, reducing the dose of smoothened in a patched background enhances the head defects. Consistent with these results, gain-of-function Hedgehog interferes with the activation of Baboon by Patched and Smoothened, leading to a similar head capsule defect. Expression of an activated form of Baboon in the patched domain in a patched mutant background completely rescues the head defects. These results provide insight into head morphogenesis, a process we know very little about, and reveal an unexpected non-canonical positive signaling pathway in which Patched and Smoothened function to promote cell proliferation as opposed to repressing it.

The segment polarity gene armadillo interacts with the wingless signaling pathway in both embryonic and adult pattern formation

Development ◽  
1991 ◽  
Vol 111 (4) ◽  
pp. 1029-1043 ◽  
Author(s):  
M. Peifer ◽  
C. Rauskolb ◽  
M. Williams ◽  
B. Riggleman ◽  
E. Wieschaus
Keyword(s):  
Pattern Formation ◽  
Imaginal Discs ◽  
Protein Accumulation ◽  
Segment Polarity Genes ◽  
Adult Pattern ◽  
Segment Polarity ◽  
Lethal Allele ◽  
Segment Polarity Gene ◽  
Polarity Gene

The segment polarity genes of Drosophila were initially defined as genes required for pattern formation within each embryonic segment. Some of these genes also function to establish the pattern of the adult cuticle. We have examined the role of the armadillo (arm) gene in this latter process. We confirmed and extended earlier findings that arm and the segment polarity gene wingless are very similar in their effects on embryonic development. We next discuss the role of arm in pattern formation in the imaginal discs, as determined by using a pupal lethal allele, by analyzing clones of arm mutant tissue in imaginal discs, and by using a transposon carrying arm to produce adults with a reduced level of arm. Together, these experiments established that arm is required for the development of all imaginal discs. The requirement for arm varies along the dorsal-ventral and proximal-distal axes. Cells that require the highest levels of arm are those that express the wingless gene. Further, animals with reduced arm levels have phenotypes that resemble those of weak alleles of wingless. We present a description of the patterns of arm protein accumulation in imaginal discs. Finally, we discuss the implications of these results for the role of arm and wingless in pattern formation.

Imaginal discs can be recovered from cultured embryos mutant for the segment-polarity genes engrailed, naked and patched but not from wingless

Development ◽  
1989 ◽  
Vol 107 (4) ◽  
pp. 715-722 ◽  
Author(s):  
A.A. Simcox ◽  
I.J.H. Roberts ◽  
E. Hersperger ◽  
M.C. Gribbin ◽  
A. Shearn ◽  
...  
Keyword(s):  
Imaginal Discs ◽  
Larval Cuticle ◽  
Segment Polarity Genes ◽  
Abnormal Morphology ◽  
In Vivo Culture ◽  
Segment Polarity ◽  
Abnormal Pattern ◽  
Drosophila Embryos

Drosophila embryos homozygous for strong mutations in each of the segment-polarity genes wingless (wg), engrailed (en), naked (nkd) and patched (ptc) form a larval cuticle in which there is a deletion in every segment. The mutant embryos normally fail to hatch but by in vivo culture we were able to show which could produce adult structures. Cultured wg- embryos did not produce any adult structures. Cultured en- embryos produced eye-antennal derivatives and rarely produced partial thoracic structures. nkd- and ptc- embryos produced eye-antennal and thoracic derivatives. The nkd- and ptc- thoracic imaginal discs developed with an abnormal morphology and abnormal pattern of en- expression. Our findings are consistent with the idea that the thoracic imaginal discs derive from two adjacent groups of cells that express wg and en respectively in the embryo.

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
Keyword(s):  
Drosophila Melanogaster ◽  
Imaginal Disc ◽  
Compound Eye ◽  
Head Capsule ◽  
Imaginal Discs ◽  
Model System ◽  
Morphogenetic Furrow ◽  
Excellent Model ◽  
Eye Disc ◽  
Antennal Disc

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.

Pattern formation in Drosophila head development: the role of the orthodenticle homeobox gene

Development ◽  
1995 ◽  
Vol 121 (11) ◽  
pp. 3561-3572 ◽  
Author(s):  
J. Royet ◽  
R. Finkelstein
Keyword(s):  
Drosophila Melanogaster ◽  
Pattern Formation ◽  
Homeobox Gene ◽  
Significant Progress ◽  
Medial Head ◽  
Head Development ◽  
Segment Polarity ◽  
Segment Polarity Gene ◽  
Polarity Gene

Significant progress has been made towards understanding how pattern formation occurs in the imaginal discs that give rise to the limbs of Drosophila melanogaster. Here, we examine the process of regional specification that occurs in the eye-antennal discs, which form the head of the adult fruitfly. We demonstrate genetically that there is a graded requirement for the activity of the orthodenticle homeobox gene in forming specific structures of the developing head. Consistent with this result, we show that OTD protein is expressed in a graded fashion across the disc primordia of these structures and that different threshold levels of OTD are required for the formation of specific subdomains of the head. Finally, we provide evidence suggesting that otd acts through the segment polarity gene engrailed to specify medial head development.

scholarly journals Successive specification of Drosophila neuroblasts NB 6-4 and NB 7-3 depends on interaction of the segment polarity genes wingless, gooseberry and naked cuticle

Development ◽  
2001 ◽  
Vol 128 (17) ◽  
pp. 3253-3261 ◽  
Author(s):  
Nirupama Deshpande ◽  
Rainer Dittrich ◽  
Gerhard M. Technau ◽  
Joachim Urban
Keyword(s):  
Cell Fate ◽  
Cell Lineage ◽  
Positional Information ◽  
Dorsoventral Patterning ◽  
Expression Domain ◽  
Direct Role ◽  
Segment Polarity Genes ◽  
Segment Polarity ◽  
Unique Identity

The Drosophila central nervous system derives from neural precursor cells, the neuroblasts (NBs), which are born from the neuroectoderm by the process of delamination. Each NB has a unique identity, which is revealed by the production of a characteristic cell lineage and a specific set of molecular markers it expresses. These NBs delaminate at different but reproducible time points during neurogenesis (S1-S5) and it has been shown for early delaminating NBs (S1/S2) that their identities depend on positional information conferred by segment polarity genes and dorsoventral patterning genes. We have studied mechanisms leading to the fate specification of a set of late delaminating neuroblasts, NB 6-4 and NB 7-3, both of which arise from the engrailed (en) expression domain, with NB 6-4 delaminating first. In contrast to former reports, we did not find any evidence for a direct role of hedgehog in the process of NB 7-3 specification. Instead, we present evidence to show that the interplay of the segmentation genes naked cuticle (nkd) and gooseberry (gsb), both of which are targets of wingless (wg) activity, leads to differential commitment to NB 6-4 and NB 7-3 cell fate. In the absence of either nkd or gsb, one NB fate is replaced by the other. However, the temporal sequence of delamination is maintained, suggesting that formation and specification of these two NBs are under independent control.

Transcription of the segment-polarity gene wingless in the imaginal discs of Drosophila, and the phenotype of a pupal-lethal wg mutation

Development ◽  
1988 ◽  
Vol 102 (3) ◽  
pp. 489-497 ◽  
Author(s):  
N.E. Baker
Keyword(s):  
In Situ Hybridization ◽  
Imaginal Discs ◽  
Apical Cytoplasm ◽  
Segment Polarity ◽  
Disc Cells ◽  
Segment Polarity Gene ◽  
Drosophila Embryos ◽  
Polarity Gene

Wingless (wg) is a segment-polarity gene in Drosophila which is related to the murine proto-oncogene int1. In Drosophila embryos, wg transcription defines part of each parasegment. In situ hybridization shows that wg is also expressed in the imaginal discs which give rise to the adult during metamorphosis. Transcripts are localized in the apical cytoplasm of disc cells, and accumulate in different patterns in dorsal and ventral discs. The wgCX3 mutation produces morphological defect in the adult structures derived from these imaginal discs. The results show that wg is involved in the development of the adult, as well as the embryo, but that the imaginal discs do not express this segment-polarity gene in an identical pattern to the embryonic segments.

scholarly journals 1 (2)gl gene regulates late expression of segment polarity genes in Drosophila

1995 ◽  
Vol 51 (2-3) ◽  
pp. 227-234 ◽  
Author(s):  
Ashim Mukherjee ◽  
S.C. Lakhotia ◽  
J.K. Roy
Keyword(s):  
Segment Polarity Genes ◽  
Segment Polarity ◽  
Late Expression

scholarly journals Studying the effect of cell division on expression patterns of the segment polarity genes

2008 ◽  
Vol 5 (suppl_1) ◽  
Author(s):  
Madalena Chaves ◽  
Réka Albert
Keyword(s):  
Cell Division ◽  
Expression Patterns ◽  
Gene Expression Pattern ◽  
Specific Gene ◽  
Biological Processes ◽  
Segment Polarity Genes ◽  
Genes Expression ◽  
Its Gene ◽  
Segment Polarity ◽  
Segment Polarity Gene

The segment polarity gene family, and its gene regulatory network, is at the basis of Drosophila embryonic development. The network's capacity for generating and robustly maintaining a specific gene expression pattern has been investigated through mathematical modelling. The models have provided several useful insights by suggesting essential network links, or uncovering the importance of the relative time scales of different biological processes in the formation of the segment polarity genes' expression patterns. But the developmental pattern formation process raises many other questions. Two of these questions are analysed here: the dependence of the signalling protein sloppy paired on the segment polarity genes and the effect of cell division on the segment polarity genes' expression patterns. This study suggests that cell division increases the robustness of the segment polarity network with respect to perturbations in biological processes.

scholarly journals Modulation of Hedgehog target gene expression by the Fused serine–threonine kinase in wing imaginal discs

1998 ◽  
Vol 78 (1-2) ◽  
pp. 17-31 ◽  
Author(s):  
Georges Alves ◽  
Bernadette Limbourg-Bouchon ◽  
Hervé Tricoire ◽  
Jeanine Brissard-Zahraoui ◽  
Claudie Lamour-Isnard ◽  
...  
Keyword(s):  
Gene Expression ◽  
Target Gene ◽  
Imaginal Discs ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Target Gene Expression ◽  
Wing Imaginal Discs
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