Regulation of ocellar specification and size by <i>twin of eyeless</i> and <i>homothorax</i>

Brockmann, Anette; Dominguez-Cejudo, Maria A; Amore, Gabriele; Casares, Fernando

doi:10.1002/dvdy.22494

Cited by 29 publications

(34 citation statements)

References 52 publications

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“…Therefore, the expression of eya and so is mutually dependent, although this dependence for eya might be only partial. A feedback between eya and so has also been described during eye and ocelli development (Pignoni et al, 1997;Brockmann et al, 2011). eya and so are required for dac expression dac expression is known to lie downstream of eya and so in the compound eye (Chen et al, 1997).…”

Section: Mutual Feedback Of Eya and Somentioning

confidence: 98%

A conserved transcriptional network regulates lamina development in the Drosophila visual system

2014

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The visual system of insects is a multilayered structure composed externally by the compound eye and internally by the three ganglia of the optic lobe: lamina, medulla and the lobula complex. The differentiation of lamina neurons depends heavily on Hedgehog (Hh) signaling, which is delivered by the incoming photoreceptor axons, and occurs in a wave-like fashion. Despite the primary role of lamina neurons in visual perception, it is still unclear how these neurons are specified from neuroepithelial (NE) progenitors. Here we show that a homothorax (hth)-eyes absent (eya)-sine oculis (so)-dachshund (dac) gene regulatory cassette is involved in this specification. Lamina neurons differentiate from NE progenitors that express hth, eya and so. One of the first events in the differentiation of lamina neurons is the upregulation of dac expression in response to Hh signaling. We show that this dac upregulation, which marks the transition from NE progenitors into lamina precursors, also requires Eya/So, the expression of which is locked in by mutual feedback. dac expression is crucial for lamina differentiation because it ensures repression of hth, a negative regulator of single-minded, and thus dac allows further lamina neuron differentiation. Therefore, the specification of lamina neurons is controlled by coupling the cell-autonomous hth-eya-so-dac regulatory cassette to Hh signaling.

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Section: Mutual Feedback Of Eya and Somentioning

confidence: 98%

A conserved transcriptional network regulates lamina development in the Drosophila visual system

2014

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“…Here, the ocellar field is specified by the action of, at least, two transcription factors: the pax6 gene twin of eyeless (toy) and the Otx family member orthodenticle (otd) (ocelliless, oc -FlyBase) (Finkelstein et al, 1990;Wieschaus et al, 1992;Royet and Finkelstein, 1995;Punzo et al, 2002;Blanco et al, 2010;Wang et al, 2010;Brockmann et al, 2011). hh is expressed within the ocellar field in the prospective interocellar region (Royet and Finkelstein, 1996;Royet and Finkelstein, 1997).…”

Section: Introductionmentioning

confidence: 99%

A Hh-driven gene network controls specification, pattern and size of the Drosophila simple eyes

Aguilar-Hidalgo

Dominguez-Cejudo

Amore³

et al. 2013

Development

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SUMMARYDuring development, extracellular signaling molecules interact with intracellular gene networks to control the specification, pattern and size of organs. One such signaling molecule is Hedgehog (Hh). Hh is known to act as a morphogen, instructing different fates depending on the distance to its source. However, how Hh, when signaling across a cell field, impacts organ-specific transcriptional networks is still poorly understood. Here, we investigate this issue during the development of the Drosophila ocellar complex. The development of this sensory structure, which is composed of three simple eyes (or ocelli) located at the vertices of a triangular patch of cuticle on the dorsal head, depends on Hh signaling and on the definition of three domains: two areas of eya and so expression -the prospective anterior and posterior ocelli -and the intervening interocellar domain. Our results highlight the role of the homeodomain transcription factor engrailed (en) both as a target and as a transcriptional repressor of hh signaling in the prospective interocellar region. Furthermore, we identify a requirement for the Notch pathway in the establishment of en maintenance in a Hh-independent manner. Therefore, hh signals transiently during the specification of the interocellar domain, with en being required here for hh signaling attenuation. Computational analysis further suggests that this network design confers robustness to signaling noise and constrains phenotypic variation. In summary, using genetics and modeling we have expanded the ocellar gene network to explain how the interaction between the Hh gradient and this gene network results in the generation of stable mutually exclusive gene expression domains. In addition, we discuss some general implications our model may have in some Hh-driven gene networks.

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“…The genes which are involved in the development are categorised as developmental gene, and the one which are involved in the functioning are classified as functional genes of ocelli. Imaginal disc development and morphogenesis [58] eyes absent Cell specification; inhibits cell death in eye imaginal disc. Cone cell differentiation.…”

Section: Genes Regulating the Development And Maintenance Of Ocellimentioning

confidence: 99%

“…Formation of morphogenetic furrow. [58] Toy Important for activation of sine oculis and ocelli formation.…”

Section: Genes Regulating the Development And Maintenance Of Ocellimentioning

confidence: 99%

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Understanding the Structural and Developmental Aspect of Simple Eye of Drosophila: The Ocelli

Sabat¹,

Priyadarsini²,

Mishra³

2017

J Cell Signal

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Among various photoreceptors present in arthropods Drosophila eye undergoes certain modification to provide high resolution and sensitivity to the animal. Along with the compound eye Drosophila possess three ocelli for its vision, navigation and locomotion purpose. These ocelli are arranged in a triangular manner in between the compound eye. During third instar larvae, from the eye antenna imaginal disc several conserved genes and complex regulatory genetic network help in ocellar patterning. Like compound eye ocelli possess cornea, corneagenous cell, photoreceptor cells (rhabdom). The visual pigment present in ocelli is Rh2 and is responsible for the functioning of ocelli. Although rhabdomere are the photoreceptor organ of the ocelli the arrangement of the rhabdomere in ocelli differs from the compound eye. Interrhabdomereal space which is present between the rhabdomeres of photoreceptor cells are absent in ocelli. The rhabdom is confined only to the apical one-third of the ocelli whereas it expands throughout the length in compound eye. The structural difference present in the compound eye and ocelli enable us to study the functioning of one gene in different photoreceptors within an animal. Thus understanding the mechanism of ocellar development, genes involved in the functioning of ocelli will help us to understand the functioning of various genes in different photoreceptor. The current article summarises the structure, function and genes involved in the development of ocelli.

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Regulation of ocellar specification and size by twin of eyeless and homothorax

Cited by 29 publications

References 52 publications

A conserved transcriptional network regulates lamina development in the Drosophila visual system

A conserved transcriptional network regulates lamina development in the Drosophila visual system

A Hh-driven gene network controls specification, pattern and size of the Drosophila simple eyes

Understanding the Structural and Developmental Aspect of Simple Eye of Drosophila: The Ocelli

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