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.

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.

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.

Hedgehog is required for activation of engrailed during regeneration of fragmented Drosophila imaginal discs

Development ◽  
1999 ◽  
Vol 126 (8) ◽  
pp. 1591-1599 ◽  
Author(s):  
M.C. Gibson ◽  
G. Schubiger
Keyword(s):  
Normal Growth ◽  
Imaginal Discs ◽  
Ideal Model ◽  
Posterior Compartment ◽  
Anterior Compartment ◽  
In Vivo Culture ◽  
Pattern Regulation ◽  
Regulative Capacity ◽  
Anterior Posterior

Surgically fragmented Drosophila appendage primordia (imaginal discs) engage in wound healing and pattern regulation during short periods of in vivo culture. Prothoracic leg disc fragments possess exceptional regulative capacity, highlighted by the ability of anterior cells to convert to posterior identity and establish a novel posterior compartment. This anterior/posterior conversion violates developmental lineage restrictions essential for normal growth and patterning of the disc, and thus provides an ideal model for understanding how cells change fate during epimorphic pattern regulation. Here we present evidence that the secreted signal encoded by hedgehog directs anterior/posterior conversion by activating the posterior-specific transcription factor engrailed in regulating anterior cells. In the absence of hedgehog activity, prothoracic leg disc fragments fail to undergo anterior/posterior conversion, but can still regenerate missing anterior pattern elements. We suggest that hedgehog-independent regeneration within the anterior compartment (termed integration) is mediated by the positional cues encoded by wingless and decapentaplegic. Taken together, our results provide a novel mechanistic interpretation of imaginal disc pattern regulation and permit speculation that similar mechanisms could govern appendage regeneration in other organisms.

Segment polarity gene interactions modulate epidermal patterning in Drosophila embryos

Development ◽  
1993 ◽  
Vol 119 (2) ◽  
pp. 501-517 ◽  
Author(s):  
A. Bejsovec ◽  
E. Wieschaus
Keyword(s):  
Cell Types ◽  
Epidermal Cells ◽  
Specific Cell ◽  
Wild Type ◽  
Individual Gene ◽  
Segment Polarity Genes ◽  
Segment Polarity ◽  
Drosophila Larva ◽  
Cuticular Structures ◽  
Drosophila Embryos

Each segment of a Drosophila larva shows a precisely organized pattern of cuticular structures, indicating diverse cellular identities in the underlying epidermis. Mutations in the segment polarity genes alter the cuticle pattern secreted by the epidermal cells; these mutant patterns provide clues about the role that each gene product plays in the development of wild-type epidermal pattern. We have analyzed embryos that are multiply mutant for five key patterning genes: wingless, patched, engrailed, naked and hedgehog. Our results indicate that wild-type activity of these five segment polarity genes can account for most of the ventral pattern elements and that their gene products interact extensively to specify the diverse cellular identities within the epidermis. Two pattern elements can be correlated with individual gene action: wingless is required for formation of naked cuticle and engrailed is required for formation of the first row of denticles in each abdominal denticle belt. The remaining cell types can be produced by different combinations of the five gene activities. wingless activity generates the diversity of cell types within the segment, but each specific cell identity depends on the activity of patched, engrailed, naked and hedgehog. These molecules modulate the distribution and interpretation of wingless signalling activity in the ventral epidermal cells and, in addition, each can contribute to pattern through a pathway independent of the wingless signalling pathway.

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.

Effect of 5-bromodeoxyuridine on pupariation and adult differentiation in the flesh fly, Sarcophaga bullata

1984 ◽  
Vol 62 (2) ◽  
pp. 157-160
Author(s):  
P. Sivasubramanian
Keyword(s):  
Imaginal Discs ◽  
Flesh Fly ◽  
Biochemical Processes ◽  
Sarcophaga Bullata ◽  
In Vivo Culture ◽  
Two Stages ◽  
Third Instar Larvae

Two stages of postfeeding, third-instar larvae of Sarcophaga bullata were injected with 5-bromodeoxyuridine to examine the effect of the analogue on pupariation and adult differentiation. While pupariation was inhibited in prered spiracle-stage larvae, adult differentiation was unaffected in both stages as revealed by in vivo culture of imaginal discs. It is suggested BudR may be more effective in disturbing certain biochemical processes than in inhibiting morphogenesis.

Control of segmental asymmetry in Drosophila embryos

Development ◽  
1993 ◽  
Vol 118 (3) ◽  
pp. 785-796 ◽  
Author(s):  
A.S. Manoukian ◽  
H.M. Krause
Keyword(s):  
Double Negative ◽  
Common Theme ◽  
Negative Regulators ◽  
Fushi Tarazu ◽  
Segment Polarity Genes ◽  
Segment Polarity ◽  
Body Patterning ◽  
Blastoderm Stage ◽  
Pair Rule ◽  
Drosophila Embryos

During Drosophila development, an important aspect of body patterning is the division of the embryo into repeating morphological units referred to as parasegments. The parasegmental domains are first defined at the blastoderm stage by alternating stripes of transcripts encoded by the pair-rule genes fushi tarazu (ftz) and even-skipped (eve) and later by stripes encoded by the segment polarity genes engrailed (en) and wingless. Here, we show that the runt gene (run) is required to generate asymmetries within these parasegmental domains. Using a heat-shock-inducible run transgene, we found that ectopic run expression leads to rapid repression of eve stripes and a somewhat delayed expansion of ftz stripes. Unexpectedly, we also found that ectopic run was a rapid and potent repressor of odd-numbered en stripes. Two remarkably different segmental phenotypes were generated as a consequence of these effects. In solving the mechanisms underlying these phenotypes, we discovered that the positioning of en stripes is largely determined by the actions of negative regulators. Our data indicate that run is required to limit the domains of en expression in the odd-numbered parasegments, while the odd-skipped gene is required to limit the domains of en expression in the even-numbered parasegments. Activation of en at the anterior margins of both sets of parasegments requires the repression of run and odd by the product of the eve gene. The spatial restriction of gene expression via negative and double negative pathways such as these is likely to be a common theme during development.

The origin of pattern duplications in segment polarity mutants of Drosophila melanogaster

Development ◽  
1985 ◽  
Vol 87 (1) ◽  
pp. 129-135
Author(s):  
Alfonso Martinez-Arias ◽  
Philip W. Ingham
Keyword(s):  
Drosophila Melanogaster ◽  
Bithorax Complex ◽  
Anterior Compartment ◽  
Larval Cuticle ◽  
Segment Polarity ◽  
Reversed Polarity ◽  
Segmental Identity

Mutations of the segment polarity group in Drosophila melanogaster produce additional denticles with reversed polarity in every segment of the larval cuticle. We have investigated the effect of mutations in different elements of the bithorax complex on the segmental identity of these additional pattern elements. Our results suggest that they are derived, primarily, from the anterior compartment of each segment.

In vivo culture of blood cells

1969 ◽  
Vol 72 (2) ◽  
pp. 304-319 ◽  
Author(s):  
Olav Hjortdal ◽  
P. Rasmussen
Keyword(s):  
Blood Cells ◽  
In Vivo Culture

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.

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