Epithelial planar polarity in the developing Drosophila eye

Development ◽  
1995 ◽  
Vol 121 (8) ◽  
pp. 2451-2459 ◽  
Author(s):  
M. Wehrli ◽  
A. Tomlinson
Keyword(s):  
Positional Information ◽  
Reverse Direction ◽  
Local Orientation ◽  
Planar Polarity ◽  
Drosophila Eye ◽  
Retinal Epithelium

Experiments with the insect ectoderm have suggested that planar polarity in epithelia results from the local orientation of cells to the slope of a gradient of positional information. Here we show that planar polarity in the Drosophila eye is inverted when the morphogenetic wave that sweeps through the presumptive retinal epithelium is induced to move in the reverse direction. We suggest that the movement of the morphogenetic wave may be causal in establishing the planar polarity of this epithelium.

Jun mediates Frizzled-induced R3/R4 cell fate distinction and planar polarity determination in the Drosophila eye

Development ◽  
2000 ◽  
Vol 127 (16) ◽  
pp. 3619-3629 ◽  
Author(s):  
U. Weber ◽  
N. Paricio ◽  
M. Mlodzik
Keyword(s):  
Cell Fate ◽  
Genetic Interaction ◽  
Function Analysis ◽  
Loss Of Function ◽  
Planar Polarity ◽  
Jnk Signaling ◽  
Drosophila Eye ◽  
Polarity Determination ◽  
Signaling Components

Jun acts as a signal-regulated transcription factor in many cellular decisions, ranging from stress response to proliferation control and cell fate induction. Genetic interaction studies have suggested that Jun and JNK signaling are involved in Frizzled (Fz)-mediated planar polarity generation in the Drosophila eye. However, simple loss-of-function analysis of JNK signaling components did not show comparable planar polarity defects. To address the role of Jun and JNK in Fz signaling, we have used a combination of loss- and gain-of-function studies. Like Fz, Jun affects the bias between the R3/R4 photoreceptor pair that is critical for ommatidial polarity establishment. Detailed analysis of jun(−) clones reveals defects in R3 induction and planar polarity determination, whereas gain of Jun function induces the R3 fate and associated polarity phenotypes. We find also that affecting the levels of JNK signaling by either reduction or overexpression leads to planar polarity defects. Similarly, hypomorphic allelic combinations and overexpression of the negative JNK regulator Puckered causes planar polarity eye phenotypes, establishing that JNK acts in planar polarity signaling. The observation that Dl transcription in the early R3/R4 precursor cells is deregulated by Jun or Hep/JNKK activation, reminiscent of the effects seen with Fz overexpression, suggests that Jun is one of the transcription factors that mediates the effects of fz in planar polarity generation.

scholarly journals Nuclear signaling by Rac and Rho GTPases is required in the establishment of epithelial planar polarity in the Drosophila eye

2000 ◽  
Vol 10 (16) ◽  
pp. 979-S1 ◽  
Author(s):  
Manolis Fanto ◽  
Ursula Weber ◽  
David I. Strutt ◽  
Marek Mlodzik
Keyword(s):  
Rho Gtpases ◽  
Planar Polarity ◽  
Nuclear Signaling ◽  
Drosophila Eye

Role of the morphogenetic furrow in establishing polarity in the Drosophila eye

Development ◽  
1995 ◽  
Vol 121 (12) ◽  
pp. 4085-4094 ◽  
Author(s):  
F. Chanut ◽  
U. Heberlein
Keyword(s):  
Ectopic Expression ◽  
Morphogenetic Furrow ◽  
Eye Disc ◽  
Drosophila Eye ◽  
Retinal Epithelium ◽  
Anteroposterior Polarity ◽  
Crystalline Array

The Drosophila retina is a crystalline array of 800 ommatidia whose organization and assembly suggest polarization of the retinal epithelium along anteroposterior and dorsoventral axes. The retina develops by a stepwise process following the posterior-to-anterior progression of the morphogenetic furrow across the eye disc. Ectopic expression of hedgehog or local removal of patched function generates ectopic furrows that can progress in any direction across the disc leaving in their wake differentiating fields of ectopic ommatidia. We have studied the effect of these ectopic furrows on the polarity of ommatidial assembly and rotation. We find that the anteroposterior asymmetry of ommatidial assembly parallels the progression of ectopic furrows, regardless of their direction. In addition, ommatidia developing behind ectopic furrows rotate coordinately, forming equators in various regions of the disc. Interestingly, the expression of a marker normally restricted to the equator is induced in ectopic ommatidial fields. Ectopic equators are stable as they persist to adulthood, where they can coexist with the normal equator. Our results suggest that ectopic furrows can impart polarity to the disc epithelium, regarding the direction of both assembly and rotation of ommatidia. We propose that these processes are polarized as a consequence of furrow propagation, while more global determinants of dorsoventral and anteroposterior polarity may act less directly by determining the site of furrow initiation.

Decoding vectorial information from a gradient: sequential roles of the receptors Frizzled and Notch in establishing planar polarity in the Drosophila eye

Development ◽  
1999 ◽  
Vol 126 (24) ◽  
pp. 5725-5738 ◽  
Author(s):  
A. Tomlinson ◽  
G. Struhl
Keyword(s):  
High Activity ◽  
Cell Fate ◽  
Photoreceptor Cells ◽  
The Other ◽  
Cell Fate Decision ◽  
Planar Polarity ◽  
Genetic Mosaics ◽  
Polar Cell ◽  
Drosophila Eye ◽  
Fate Decision

The Drosophila eye is composed of several hundred ommatidia that can exist in either of two chiral forms, depending on position: ommatidia in the dorsal half of the eye adopt one chiral form, whereas ommatidia in the ventral half adopt the other. Chirality appears to be specified by a polarizing signal with a high activity at the interface between the two halves (the ‘equator’), which declines in opposite directions towards the dorsal and ventral poles. Here, using genetic mosaics, we show that this polarizing signal is decoded by the sequential use of two receptor systems. The first depends on the seven-transmembrane receptor Frizzled (Fz) and distinguishes between the two members of the R3/R4 pair of presumptive photoreceptor cells, predisposing the cell that is located closer to the equator and having higher Fz activity towards the R3 photoreceptor fate and the cell further away towards the R4 fate. This bias is then amplified by subsequent interactions between the two cells mediated by the receptor Notch (N) and its ligand Delta (Dl), ensuring that the equatorial cell becomes the R3 photoreceptor while the polar cell becomes the R4 photoreceptor. As a consequence of this reciprocal cell fate decision, the R4 cell moves asymmetrically relative to the R3 cell, initiating the appropriate chiral pattern of the remaining cells of the ommatidium.

The presumptive R7 cell of the developing Drosophila eye receives positional information independent of sevenless, boss and sina

1992 ◽  
Vol 37 (1-2) ◽  
pp. 37-42 ◽  
Author(s):  
Marek Mlodzik ◽  
Yasushi Hiromi ◽  
Corey S. Goodman ◽  
Gerald M. Rubin
Keyword(s):  
Positional Information ◽  
Drosophila Eye

Drosophila eye disc margin is a center for organizing long-range planar polarity

genesis ◽  
2004 ◽  
Vol 39 (1) ◽  
pp. 26-37 ◽  
Author(s):  
Janghoo Lim ◽  
Kwang-Wook Choi
Keyword(s):  
Long Range ◽  
Planar Polarity ◽  
Eye Disc ◽  
Drosophila Eye

Asymmetric Notch activation specifies photoreceptors R3 and R4 and planar polarity in the Drosophila eye

Nature ◽  
10.1038/17389 ◽  
1999 ◽  
Vol 397 (6719) ◽  
pp. 523-526 ◽  
Author(s):  
Manolis Fanto ◽  
Marek Mlodzik
Keyword(s):  
Planar Polarity ◽  
Drosophila Eye ◽  
Notch Activation

Linking Frizzled and Wnt signaling in Drosophila development

Development ◽  
1997 ◽  
Vol 124 (22) ◽  
pp. 4515-4521 ◽  
Author(s):  
A. Tomlinson ◽  
W.R. Strapps ◽  
J. Heemskerk
Keyword(s):  
Wnt Signaling ◽  
Signaling Pathway ◽  
Wnt Pathway ◽  
Wnt Signaling Pathway ◽  
Loss Of Function ◽  
Planar Polarity ◽  
Culture Cells ◽  
Second Messenger Systems ◽  
Retinal Epithelium ◽  
Embryonic Ectoderm

Drosophila Frizzled-2 (Dfz2) has been identified as a putative fly Wingless (Wg) receptor. Although Dfz2 shows significant homology with Fz, a protein that operates in the mechanisms that establish planar polarity in Drosophila epithelia, any clear evidence for an involvement by Fz in a Wnt signaling pathway has hitherto been absent. Here we describe the planar polarity phenotypes of loss-of-function and overexpression of Fz in the developing Drosophila eye and find it almost identical to the loss-of-function or overexpression of Dishevelled (Dsh - a protein operating in Wnt second messenger systems). In addition, we show that overexpression of Shaggy (Sgg - another component of the Wnt pathway) in the eye also causes a phenotype similar to Fz and Dsh. To test further the link between planar polarity and Wnt signaling we misexpressed Wg in the developing eye and found it had a potent polarizing effect in the retinal epithelium. Since the overexpression of Fz in the developing eye gave a phenotype consistent with activating the Wnt pathway, we tested overexpression of Fz in the developing embryonic ectoderm and found that it phenocopied overexpression of Wg. To check that Fz was indeed able to activate a Wnt pathway we overexpressed it in Drosophila tissue culture cells and observed the characteristic phosphorylation of Dsh that occurs in response to Wnt signaling. Taken together our results significantly strengthen the case for Fz acting in a Wnt signaling pathway in Drosophila.

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