scholarly journals Dorsoventral patterning in the Drosophila retina by wingless

Development ◽  
1998 ◽  
Vol 125 (4) ◽  
pp. 567-577 ◽  
Author(s):  
U. Heberlein ◽  
E.R. Borod ◽  
F.A. Chanut
Keyword(s):  
Posterior Margin ◽  
Imaginal Disc ◽  
Mirror Image ◽  
Dorsoventral Patterning ◽  
Multiple Events ◽  
Ommatidial Rotation ◽  
Necessary And Sufficient ◽  
Eye Imaginal Disc ◽  
Anterior Posterior ◽  
Epithelial Growth

The eye imaginal disc displays dorsal-ventral (D-V) and anterior-posterior polarity prior to the onset of differentiation, which initiates at the intersection of the D-V midline with the posterior margin. As the wave of differentiation progresses anteriorly, additional asymmetry develops as ommatidial clusters rotate coordinately in opposite directions in the dorsal and ventral halves of the disc; this forms a line of mirror-image symmetry, the equator, which coincides with the D-V midline of the disc. How D-V pattern is established and how it relates to ommatidial rotation are unknown. Here we address this question by assaying the expression of various asymmetric markers under conditions that lead to ectopic differentiation, such as removal of patched or wingless function. We find that D-V patterning develops gradually and that wingless plays an important role in setting up this pattern. We show that wingless is necessary and sufficient to induce dorsal expression of the gene mirror prior to the start of differentiation and also to restrict the expression of the WR122 marker to differentiating photoreceptors near the equator. In addition, we find that manipulations in wingless expression shift the D-V axis of the disc as evidenced by changes in the expression domains of asymmetric markers, the position of the site of initiation and the equator, and the pattern of epithelial growth. Thus, Wg appears to coordinately regulate multiple events related to D-V patterning in the developing retina.

decapentaplegic and wingless are regulated by eyes absent and eyegone and interact to direct the pattern of retinal differentiation in the eye disc

Development ◽  
1998 ◽  
Vol 125 (18) ◽  
pp. 3741-3751 ◽  
Author(s):  
D.J. Hazelett ◽  
M. Bourouis ◽  
U. Walldorf ◽  
J.E. Treisman
Keyword(s):  
Posterior Margin ◽  
Imaginal Disc ◽  
Anterior Margin ◽  
Growth Factor Receptor ◽  
Eyes Absent ◽  
Retinal Tissue ◽  
Eye Disc ◽  
Epidermal Growth ◽  
Lateral Margins ◽  
Eye Imaginal Disc

Signaling by the secreted hedgehog, decapentaplegic and wingless proteins organizes the pattern of photoreceptor differentiation within the Drosophila eye imaginal disc; hedgehog and decapentaplegic are required for differentiation to initiate at the posterior margin and progress across the disc, while wingless prevents it from initiating at the lateral margins. Our analysis of these interactions has shown that initiation requires both the presence of decapentaplegic and the absence of wingless, which inhibits photoreceptor differentiation downstream of the reception of the decapentaplegic signal. However, wingless is unable to inhibit differentiation driven by activation of the epidermal growth factor receptor pathway. The effect of wingless is subject to regional variations in control, as the anterior margin of the disc is insensitive to wingless inhibition. The eyes absent and eyegone genes encode members of a group of nuclear proteins required to specify the fate of the eye imaginal disc. We show that both eyes absent and eyegone are required for normal activation of decapentaplegic expression at the posterior and lateral margins of the disc, and repression of wingless expression in presumptive retinal tissue. The requirement for eyegone can be alleviated by inhibition of the wingless signaling pathway, suggesting that eyegone promotes eye development primarily by repressing wingless. These results provide a link between the early specification and later differentiation of the eye disc.

dachshund encodes a nuclear protein required for normal eye and leg development in Drosophila

Development ◽  
1994 ◽  
Vol 120 (12) ◽  
pp. 3473-3486 ◽  
Author(s):  
G. Mardon ◽  
N.M. Solomon ◽  
G.M. Rubin
Keyword(s):  
Cell Fate ◽  
Posterior Margin ◽  
Imaginal Disc ◽  
Nuclear Protein ◽  
Eye Disc ◽  
Leg Development ◽  
Disc Cells ◽  
Neural Specification ◽  
Eye Imaginal Disc

Neural specification and differentiation in the Drosophila eye sweep across the unpatterned epithelial monolayer of the eye imaginal disc following a developmental wave termed the morphogenetic furrow. The furrow begins at the posterior margin of the eye imaginal disc and moves anteriorly as a linear front. Progression of the furrow requires the function of hedgehog, which encodes a secreted signaling protein. We characterize mutations in dachshund, a gene that encodes a novel nuclear protein required for normal cell-fate determination of imaginal disc cells. In the absence of dachshund function, cells at the posterior margin of the eye disc fail to follow a retinal differentiation pathway and appear to adopt a cuticle fate instead. These cells are therefore unable to respond to pattern propagation signals such as hedgehog and furrow initiation does not occur. In contrast, cells in more anterior portions of the eye disc are able to differentiate as retinal cells in the absence of dachshund activity and respond normally to patterning signals. These results suggest that posterior margin cells are distinct from other cells of the eye imaginal disc by early stages of development. dachshund is also necessary for proper differentiation of a subset of segments in the developing leg. Null mutations in dachshund result in flies with no eyes and shortened legs.

Role of decapentaplegic in initiation and progression of the morphogenetic furrow in the developing Drosophila retina

Development ◽  
1997 ◽  
Vol 124 (2) ◽  
pp. 559-567 ◽  
Author(s):  
F. Chanut ◽  
U. Heberlein
Keyword(s):  
Posterior Margin ◽  
Imaginal Disc ◽  
Photoreceptor Cells ◽  
Morphogenetic Furrow ◽  
Retinal Differentiation ◽  
Eye Disc ◽  
Forward Edge ◽  
Eye Imaginal Disc ◽  
Precise Role

Morphogenesis in the Drosophila retina initiates at the posterior margin of the eye imaginal disc by an unknown mechanism. Upon initiation, a wave of differentiation, its forward edge marked by the morphogenetic furrow (MF), proceeds anteriorly across the disc. Progression of the MF is driven by hedgehog (hh), expressed by differentiating photoreceptor cells. The TGF-beta homolog encoded by decapentaplegic (dpp) is expressed at the disc's posterior margin prior to initiation and in the furrow, under the control of hh, during MF progression. While dpp has been implicated in eye disc growth and morphogenesis, its precise role in retinal differentiation has not been determined. To address the role of dpp in initiation and progression of retinal differentiation we analyzed the consequences of reduced and increased dpp function during eye development. We find that dpp is not only required for normal MF initiation, but is sufficient to induce ectopic initiation of differentiation. Inappropriate initiation is normally inhibited by wingless (wg). Loss of dpp function is accompanied by expansion of wg expression, while increased dpp function leads to loss of wg transcription. In addition, dpp is required to maintain, and sufficient to induce, its own expression along the disc's margins. We postulate that dpp autoregulation and dpp-mediated inhibition of wg expression are required for the coordinated regulation of furrow initiation and progression. Finally, we show that in the later stages of retinal differentiation, reduction of dpp function leads to an arrest in MF progression.

scholarly journals The eye imaginal disc as a model to study the coordination of neuronal and glial development

Fly ◽  
2010 ◽  
Vol 4 (1) ◽  
pp. 71-79 ◽  
Author(s):  
Marion Silies ◽  
Yeliz Yuva-Aydemir ◽  
Sigrídur Rut Franzdottir ◽  
Christian Klämbt
Keyword(s):  
Imaginal Disc ◽  
Glial Development ◽  
Eye Imaginal Disc

scholarly journals pop-1/TCF, ref-2/ZIC and T-box factors regulate the development of anterior cells in the C. elegans embryo

2021 ◽  
Author(s):  
Jonathan D Rumley ◽  
Elicia A Preston ◽  
Dylan Cook ◽  
Felicia L Peng ◽  
Amanda L Zacharias ◽  
...  
Keyword(s):  
Wnt Pathway ◽  
Expression Patterns ◽  
Specific Expression ◽  
T Box ◽  
Animal Development ◽  
C Elegans ◽  
The Many ◽  
Necessary And Sufficient ◽  
Cell Division Timing ◽  
Anterior Posterior

Patterning of the anterior-posterior axis is fundamental to animal development. The Wnt pathway plays a major role in this process by activating the expression of posterior genes in animals from worms to humans. This observation raises the question of whether the Wnt pathway or other regulators control the expression of the many anterior-expressed genes. We found that the expression of five anterior-specific genes in Caenorhabditis elegans embryos depends on the Wnt pathway effectors pop-1/TCF and sys-1/β-catenin. We focused further on one of these anterior genes, ref-2/ZIC, a conserved transcription factor expressed in multiple anterior lineages. Live imaging of ref-2 mutant embryos identified defects in cell division timing and position in anterior lineages. Cis-regulatory dissection identified three ref-2 transcriptional enhancers, one of which is necessary and sufficient for anterior-specific expression. This enhancer is activated by the T-box transcription factors TBX-37 and TBX-38, and surprisingly, concatemerized TBX-37/38 binding sites are sufficient to drive anterior-biased expression alone, despite the broad expression of TBX-37 and TBX-38. Taken together, our results highlight the diverse mechanisms used to regulate anterior expression patterns in the embryo.

Role of knot (kn) in Wing Patterning in Drosophila

Genetics ◽  
1997 ◽  
Vol 147 (3) ◽  
pp. 1203-1212 ◽  
Author(s):  
Katerina Nestoras ◽  
Helena Lee ◽  
Jym Mohler
Keyword(s):  
Hedgehog Signaling ◽  
Imaginal Disc ◽  
Hedgehog Signaling Pathway ◽  
Posterior Compartment ◽  
Drosophila Wing ◽  
Compartment Boundary ◽  
Hh Signaling ◽  
Embryonic Segmentation ◽  
Anterior Posterior

We have undertaken a genetic analysis of new strong alleles of knot (kn). The original kn1 mutation causes an alteration of wing patterning similar to that associated with mutations of fused (fu), an apparent fusion of veins 3 and 4 in the wing. However, unlike fu, strong kn mutations do not affect embryonic segmentation and indicate that kn is not a component of a general Hh (Hedgehog)-signaling pathway. Instead we find that kn has a specific role in those cells of the wing imaginal disc that are subject to ptc-mediated Hh-signaling. Our results suggest a model for patterning the medial portion of the Drosophila wing, whereby the separation of veins 3 and 4 is maintained by kn activation in the intervening region in response to Hh-signaling across the adjacent anterior-posterior compartment boundary.

slimb coordinates wg and dpp expression in the dorsal-ventral and anterior-posterior axes during limb development

Development ◽  
1998 ◽  
Vol 125 (17) ◽  
pp. 3411-3416 ◽  
Author(s):  
N.A. Theodosiou ◽  
S. Zhang ◽  
W.Y. Wang ◽  
T. Xu
Keyword(s):  
Genetic Analysis ◽  
Limb Development ◽  
Imaginal Disc ◽  
Essential Role ◽  
Present Evidence ◽  
First Time ◽  
Anterior Posterior

In the Drosophila leg disc, wingless (wg) and decapentaplegic (dpp) are expressed in a ventral-anterior and dorsal-anterior stripe of cells, respectively. This pattern of expression is essential for proper limb development. While the Hedgehog (Hh) pathway regulates dpp and wg expression in the anterior-posterior (A/P) axis, mechanisms specifying their expression in the dorsal-ventral (D/V) axis are not well understood. We present evidence that slimb mutant clones in the disc deregulate wg and dpp expression in the D/V axis. This suggests for the first time that their expression in the D/V axis is actively regulated during imaginal disc development. Furthermore, slimb is unique in that it also deregulates wg and dpp in the A/P axis. The misexpression phenotypes of slimb- clones indicate that the regulation of wg and dpp expression is coordinated in both axes, and that slimb plays an essential role in integrating A/P and D/V signals for proper patterning during development. Our genetic analysis further reveals that slimb intersects the A/P pathway upstream of smoothened (smo).

scholarly journals Ectopic expression of human p53 inhibits entry into S phase and induces apoptosis in the Drosophila eye imaginal disc

Oncogene ◽  
1999 ◽  
Vol 18 (48) ◽  
pp. 6767-6775 ◽  
Author(s):  
Masamitsu Yamaguchi ◽  
Fumiko Hirose ◽  
Yoshihiro H Inoue ◽  
Michina Shiraki ◽  
Yuko Hayashi ◽  
...  
Keyword(s):  
Imaginal Disc ◽  
Ectopic Expression ◽  
S Phase ◽  
Drosophila Eye ◽  
Eye Imaginal Disc

scholarly journals Live Imaging of Glial Cell Migration in the Drosophila Eye Imaginal Disc

10.3791/1155 ◽  
2009 ◽  
Author(s):  
Patrick Cafferty ◽  
Xiaojun Xie ◽  
Kristen Browne ◽  
Vanessa J. Auld
Keyword(s):  
Cell Migration ◽  
Glial Cell ◽  
Imaginal Disc ◽  
Live Imaging ◽  
Drosophila Eye ◽  
Eye Imaginal Disc
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