Cell patterning in the Drosophila segment: spatial regulation of the segment polarity gene patched

Development ◽  
1990 ◽  
Vol 110 (1) ◽  
pp. 291-301 ◽  
Author(s):  
A. Hidalgo ◽  
P. Ingham
Keyword(s):  
Broad Band ◽  
Positional Information ◽  
Drosophila Embryo ◽  
Normal Pattern ◽  
Anterior Portion ◽  
Spatial Regulation ◽  
Segment Polarity Genes ◽  
Segment Polarity ◽  
Segment Polarity Gene ◽  
Polarity Gene

Intrasegmental patterning in the Drosophila embryo requires the activity of the segment polarity genes. The acquisition of positional information by cells during embryogenesis is reflected in the dynamic patterns of expression of several of these genes. In the case of patched, early ubiquitous expression is followed by its repression in the anterior portion of each parasegment; subsequently each broad band of expression splits into two narrow stripes. In this study we analyse the contribution of other segment polarity gene functions to the evolution of this pattern; we find that the first step in patched regulation is under the control of engrailed whereas the second requires the activity of both cubitus interruptusD and patched itself. Furthermore, the products of engrailed, wingless and hedgehog are essential for maintaining the normal pattern of expression of patched.

Role of segment polarity genes in the definition and maintenance of cell states in the Drosophila embryo

Development ◽  
1988 ◽  
Vol 103 (1) ◽  
pp. 157-170 ◽  
Author(s):  
A. Martinez Arias ◽  
N.E. Baker ◽  
P.W. Ingham
Keyword(s):  
Positional Information ◽  
Drosophila Embryo ◽  
Gene Products ◽  
Segment Polarity Genes ◽  
Restricted Domains ◽  
Segment Polarity ◽  
Mutant Phenotypes ◽  
Segment Polarity Gene ◽  
Polarity Gene

Segment polarity genes are expressed and required in restricted domains within each metameric unit of the Drosophila embryo. We have used the expression of two segment polarity genes engrailed (en) and wingless (wg) to monitor the effects of segment polarity mutants on the basic metameric pattern. Absence of patched (ptc) or naked (nkd) functions triggers a novel sequence of en and wg patterns. In addition, although wg and en are not expressed on the same cells absence of either one has effects on the expression of the other. These observations, together with an analysis of mutant phenotypes during development, lead us to suggest that positional information is encoded in cell states defined and maintained by the activity of segment polarity gene products.

Regulation of wingless transcription in the Drosophila embryo

Development ◽  
1993 ◽  
Vol 117 (1) ◽  
pp. 283-291 ◽  
Author(s):  
P.W. Ingham ◽  
A. Hidalgo
Keyword(s):  
Regulatory Network ◽  
Signal Transduction Pathway ◽  
Multiple Roles ◽  
Drosophila Embryo ◽  
Transduction Pathway ◽  
Segment Polarity Genes ◽  
Segment Polarity ◽  
Segment Polarity Gene ◽  
Pair Rule ◽  
Polarity Gene

The segment polarity gene wingless (wg) is expressed in a complex pattern during embryogenesis suggesting that it plays multiple roles in the development of the embryo. The best characterized of these is its role in cell pattening in each parasegment, a process that requires the activity of other segment polarity genes including patched (ptc) and hedgehog (hh). Here we present further evidence that ptc and hh encode components of a signal transduction pathway that regulate the expression of wg transcription following its activation by pair-rule genes. We also show that most other aspects of wg expression are independent of this regulatory network.

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.

Molecular organization and embryonic expression of the hedgehog gene involved in cell-cell communication in segmental patterning of Drosophila

Development ◽  
1992 ◽  
Vol 115 (4) ◽  
pp. 957-971 ◽  
Author(s):  
J. Mohler ◽  
K. Vani
Keyword(s):  
Transmembrane Protein ◽  
Cell Communication ◽  
Protein Product ◽  
Drosophila Embryo ◽  
Molecular Organization ◽  
Posterior Portion ◽  
Segment Polarity ◽  
Segment Polarity Gene ◽  
Polarity Gene ◽  
Cell Cell

hedgehog is a segment polarity gene necessary to maintain the proper organization of each segment of the Drosophila embryo. We have identified the physical location of a number of rearrangement breakpoints associated with hedgehog mutations. The corresponding hh RNA is expressed in a series of segmental stripes starting at cellular blastoderm in the posterior portion of each segment. This RNA is localized predominantly within nuclei until stage 10, when the localization becomes primarily cytoplasmic. Expression of hh RNA in the posterior compartment is independent of most other segment polarity genes, including en, until the late extended germ-band stage (stage 11). Sequence analysis of the hedgehog locus suggests the protein product is a transmembrane protein, which may, therefore, be directly involved in cell-cell communication.

Positional signaling by hedgehog in Drosophila imaginal disc development

Development ◽  
1995 ◽  
Vol 121 (1) ◽  
pp. 1-10 ◽  
Author(s):  
A.L. Felsenfeld ◽  
J.A. Kennison
Keyword(s):  
Hedgehog Signaling ◽  
Imaginal Disc ◽  
Ectopic Expression ◽  
Posterior Compartment ◽  
Anterior Compartment ◽  
Segment Polarity ◽  
Wing Structures ◽  
Wing Discs ◽  
Segment Polarity Gene ◽  
Polarity Gene

We describe a dominant gain-of-function allele of the segment polarity gene hedgehog. This mutation causes ectopic expression of hedgehog mRNA in the anterior compartment of wing discs, leading to overgrowth of tissue in the anterior of the wing and partial duplication of distal wing structures. The posterior compartment of the wing is unaffected. Other imaginal derivatives are affected, resulting in duplications of legs and antennae and malformations of eyes. In mutant imaginal wing discs, expression of the decapentaplegic gene, which is implicated in the hedgehog signaling pathway, is also perturbed. The results suggest that hedgehog protein acts in the wing as a signal to instruct neighboring cells to adopt fates appropriate to the region of the wing just anterior to the compartmental boundary.

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.

rasp, a putative transmembrane acyltransferase, is required for Hedgehog signaling

Development ◽  
2002 ◽  
Vol 129 (4) ◽  
pp. 843-851 ◽  
Author(s):  
Craig A. Micchelli ◽  
Inge The ◽  
Erica Selva ◽  
Vladic Mogila ◽  
Norbert Perrimon
Keyword(s):  
Hedgehog Signaling ◽  
Transmembrane Protein ◽  
Post Translational Modification ◽  
Protein Levels ◽  
Lethal Mutations ◽  
Segment Polarity ◽  
Invertebrate Development ◽  
Membrane Bound ◽  
Segment Polarity Gene ◽  
Polarity Gene

Members of the Hedgehog (Hh) family encode secreted molecules that act as potent organizers during vertebrate and invertebrate development. Post-translational modification regulates both the range and efficacy of Hh protein. One such modification is the acylation of the N-terminal cysteine of Hh. In a screen for zygotic lethal mutations associated with maternal effects, we have identified rasp, a novel Drosophila segment polarity gene. Analysis of the rasp mutant phenotype, in both the embryo and wing imaginal disc demonstrates that rasp does not disrupt Wnt/Wingless signaling but is specifically required for Hh signaling. The requirement of rasp is restricted only to those cells that produce Hh; hh transcription, protein levels and distribution are not affected by the loss of rasp. Molecular analysis reveals that rasp encodes a multipass transmembrane protein that has homology to a family of membrane bound O-acyl transferases. Our results suggest that Rasp-dependent acylation is necessary to generate a fully active Hh protein.

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.

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