Eyeless initiates the expression of both sine oculis and eyes absent during Drosophila compound eye development

The Drosophila Pax-6 gene eyeless acts high up in the genetic hierarchy involved in compound eye development and can direct the formation of extra eyes in ectopic locations. Here we identify sine oculis and eyes absent as two mediators of the eye-inducing activity of eyeless. We show that eyeless induces and requires the expression of both genes independently during extra eye development. During normal eye development, eyeless is expressed earlier than and is required for the expression of sine oculis and eyes absent, but not vice versa. Based on the results presented here and those of others, we propose a model in which eyeless induces the initial expression of both sine oculis and eyes absent in the eye disc. sine oculis and eyes absent then appear to participate in a positive feedback loop that regulates the expression of all three genes. In contrast to the regulatory interactions that occur in the developing eye disc, we also show that in the embryonic head, sine oculis acts in parallel to eyeless and twin of eyeless, a second Pax-6 gene from Drosophila. Recent studies in vertebrate systems indicate that the epistatic relationships among the corresponding vertebrate homologs are very similar to those observed in Drosophila.

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Differential interactions ofeyelessandtwin of eyelesswith thesine oculisenhancer

Development ◽

10.1242/dev.129.3.625 ◽

2002 ◽

Vol 129 (3) ◽

pp. 625-634 ◽

Cited By ~ 4

Author(s):

Claudio Punzo ◽

Makiko Seimiya ◽

Susanne Flister ◽

Walter J. Gehring ◽

Serge Plaza

Keyword(s):

Binding Sites ◽

Compound Eye ◽

Eye Development ◽

Targeted Mutagenesis ◽

Hierarchical Network ◽

Eyes Absent ◽

Sine Oculis ◽

Visual Systems ◽

Rescue Experiment ◽

Functional Involvement

Drosophila eye development is under the control of early eye specifying genes including eyeless (ey), twin of eyeless (toy), eyes absent (eya), dachshund (dac) and sine oculis (so). They are all conserved between vertebrates and insects and they interact in a combinatorial and hierarchical network to regulate each other expression. so has been shown to be directly regulated by ey through an eye-specific enhancer (so10). We further studied the regulation of this element and found that both Drosophila Pax6 proteins namely EY and TOY bind and positively regulate so10 expression through different binding sites. By targeted mutagenesis experiments, we disrupted these EY and TOY binding sites and studied their functional involvement in the so10 enhancer expression in the eye progenitor cells. We show a differential requirement for the EY and TOY binding sites in activating so10 during the different stages of eye development. Additionally, in a rescue experiment performed in the so1 mutant, we show that the EY and TOY binding sites are required for compound eye and ocellus development respectively. Altogether, these results suggest a differential requirement for EY and TOY to specify the development of the two types of adult visual systems, namely the compound eye and the ocellus.

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Morphogenetic furrow initiation and progression during eye development in Drosophila: the roles of decapentaplegic, hedgehog and eyes absent

Development ◽

10.1242/dev.127.6.1325 ◽

2000 ◽

Vol 127 (6) ◽

pp. 1325-1336 ◽

Cited By ~ 11

Author(s):

J. Curtiss ◽

M. Mlodzik

Keyword(s):

Eye Development ◽

Loss Of Function ◽

Morphogenetic Furrow ◽

Eyes Absent ◽

Sine Oculis ◽

Functional Relationships ◽

Eye Disc ◽

Additional Control ◽

Redundant Functions ◽

Signaling Components

The Drosophila signaling factor decapentaplegic (dpp) mediates the effects of hedgehog (hh) in tissue patterning by regulating the expression of tissue-specific genes. In the eye disc, the transcription factors eyeless (ey), eyes absent (eya), sine oculis (so) and dachshund (dac) participate with these signaling molecules in a complex regulatory network that results in the initiation of eye development. Our analysis of functional relationships in the early eye disc indicates that hh and dpp play no role in regulating ey, but are required for eya, so and dac expression. We show that restoring expression of eya in loss-of-function dpp mutant backgrounds is sufficient to induce so and dac expression and to rescue eye development. Thus, once expressed, eya can carry out its functions in the absence of dpp. These experiments indicate that dpp functions downstream of or in parallel with ey, but upstream of eya, so and dac. Additional control is provided by a feedback loop that maintains expression of eya and so and includes dpp. The fact that exogenous overexpression of ey, eya, so and dac interferes with wild-type eye development demonstrates the importance of such a complicated mechanism for maintaining proper levels of these factors during early eye development. Whereas initiation of eye development fails in either Hh or Dpp signaling mutants, the subsequent progression of the morphogenetic furrow is only slowed down. However, we find that clones that are simultaneously mutant for Hh and Dpp signaling components completely block furrow progression and eye differentiation, suggesting that Hh and Dpp serve partially redundant functions in this process. Interestingly, furrow-associated expression of eya, so and dac is not affected by double mutant tissue, suggesting that some other factor(s) regulates their expression during furrow progression.

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The Drosophila eyes absent gene directs ectopic eye formation in a pathway conserved between flies and vertebrates

Development ◽

10.1242/dev.124.23.4819 ◽

1997 ◽

Vol 124 (23) ◽

pp. 4819-4826 ◽

Cited By ~ 11

Author(s):

N.M. Bonini ◽

Q.T. Bui ◽

G.L. Gray-Board ◽

J.M. Warrick

Keyword(s):

Gene Function ◽

Compound Eye ◽

Eye Development ◽

Control Gene ◽

Eyes Absent ◽

Regulatory Loop ◽

The Relationship ◽

Eye Formation ◽

Master Control

The fly eyes absent (eya) gene which is essential for compound eye development in Drosophila, was shown to be functionally replaceable in eye development by a vertebrate Eya homolog. The relationship between eya and that of the eyeless gene, a Pax-6 homolog, critical for eye formation in both flies and man, was defined: eya was found to be essential for eye formation by eyeless. Moreover, eya could itself direct ectopic eye formation, indicating that eya has the capacity to function as a master control gene for eye formation. Finally, we show that eya and eyeless together were more effective in eye formation than either gene alone. These data indicate conservation of the pathway of eya function between flies and vertebrates; they suggest a model whereby eya/Eya gene function is essential for eye formation by eyeless/Pax-6, and that eya/Eya can in turn mediate, via a regulatory loop, the activity of eyeless/Pax-6 in eye formation.

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Role of Serotonin Transporter in Eye Development of Drosophila melanogaster

International Journal of Molecular Sciences ◽

10.3390/ijms21114086 ◽

2020 ◽

Vol 21 (11) ◽

pp. 4086

Author(s):

Tuan L. A. Pham ◽

Tran Duy Binh ◽

Guanchen Liu ◽

Thanh Q. C. Nguyen ◽

Yen D. H. Nguyen ◽

...

Keyword(s):

Cell Death ◽

Drosophila Melanogaster ◽

Serotonin Transporter ◽

Compound Eye ◽

Eye Development ◽

S Phase ◽

Eye Disc ◽

Eye Imaginal Disc ◽

The Brain

Serotonin transporter (SerT) in the brain is an important neurotransmitter transporter involved in mental health. However, its role in peripheral organs is poorly understood. In this study, we investigated the function of SerT in the development of the compound eye in Drosophila melanogaster. We found that SerT knockdown led to excessive cell death and an increased number of cells in S-phase in the posterior eye imaginal disc. Furthermore, the knockdown of SerT in the eye disc suppressed the activation of Akt, and the introduction of PI3K effectively rescued this phenotype. These results suggested that SerT plays a role in the healthy eye development of D. melanogaster by controlling cell death through the regulation of the PI3K/Akt pathway.

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