Analyzing the role of CtBP in Drosophila eye development

The Iroquois complex (Iro-C) genes are expressed in the dorsal compartment of the Drosophila eye/antenna imaginal disc. Previous work has shown that the Iro-C homeoproteins are essential for establishing a dorsoventral pattern organizing center necessary for eye development. Here we show that, in addition, the Iro-C products are required for the specification of dorsal head structures. In mosaic animals, the removal of the Iro-C transforms the dorsal head capsule into ventral structures, namely, ptilinum, prefrons and suborbital bristles. Moreover, the Iro-C(−) cells can give rise to an ectopic antenna and maxillary palpus, the main derivatives of the antenna part of the imaginal disc. These transformations are cell-autonomous, which indicates that the descendants of a dorsal Iro-C(−) cell can give rise to essentially all the ventral derivatives of the eye/antenna disc. These results support a role of the Iro-C as a dorsal selector in the eye and head capsule. Moreover, they reinforce the idea that developmental cues inherited from the distinct embryonic segments from which the eye/antenna disc originates play a minimal role in the patterning of this disc.

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All about Drosophila eye development (almost): Drosophila Eye Development

Journal of Cell Science ◽

10.1242/jcs.00435 ◽

2003 ◽

Vol 116 (9) ◽

pp. 1650-1651

Author(s):

S. Bray

Keyword(s):

Eye Development ◽

Drosophila Eye

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

Development ◽

10.1242/dev.127.16.3619 ◽

2000 ◽

Vol 127 (16) ◽

pp. 3619-3629 ◽

Cited By ~ 6

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.

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