Sonic hedgehog, secreted by amacrine cells, acts as a short-range signal to direct differentiation and lamination in the zebrafish retina

Shkumatava, Alena; Fischer, Sabine; Müller, Ferenc; Strähle, Uwe; Neumann, Carl J.

doi:10.1242/dev.01247

Cited by 137 publications

(171 citation statements)

References 32 publications

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“…In the absence of ath5 in the lakritz mutant, neuroblasts fail to be specified as ganglion cells and remain in the cell cycle giving rise to later born cell types (Kay et al, 2001). However, expression of Sonic hedgehog by amacrine cells appears to mediate specification of the other retinal neurons (Shkumatava et al, 2004). As we have alluded to, the differentiation of the ganglion cells is followed very closely by the differentiation of amacrine cells, interneurons and retinal lamination.…”

Section: Neurogenesismentioning

confidence: 74%

“…Differentiation then spreads dorsally around to the ventral temporal retina in a wave-like manner reminiscent of the movement of the morphogenetic furrow in Drosophila (Schmitt and Dowling, 1996). Also similar to Drosophila, the wave of differentiation is associated with a wave of sonic hedgehog expression by the differentiating cells (Neumann and Nuesslein-Volhard, 2000;Shkumatava et al, 2004). The similarities do not end there.…”

Section: Neurogenesismentioning

confidence: 99%

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Zebrafish: A model system for the study of eye genetics

Fadool

Dowling

2008

Progress in Retinal and Eye Research

195

172

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Over the last decade, the use of the zebrafish as a genetic model has moved beyond the proof-ofconcept for the analysis of vertebrate embryonic development to demonstrated utility as a mainstream model organism for the understanding of human disease. The initial identification of a variety of zebrafish mutations affecting the eye and retina, and the subsequent cloning of mutated genes have revealed cellular, molecular and physiological processes fundamental to visual system development. With the increasing development of genetic manipulations, sophisticated techniques for phenotypic characterization, behavioral approaches and screening strategies, the identification of novel genes or novel gene functions will have important implications for our understanding of human eye diseases, pathogenesis, and treatment.

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Section: Neurogenesismentioning

confidence: 74%

Section: Neurogenesismentioning

confidence: 99%

Zebrafish: A model system for the study of eye genetics

Fadool

Dowling

2008

Progress in Retinal and Eye Research

195

172

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“…For example, two zebrafish hh genes, sonic hedgehog (shh) and tiggy-winkle hedgehog (twhh), are expressed in newly generated ganglion cells, and Hh signaling is required for the progression of ganglion cell differentiation (Neumann and Nuesslein-Volhard, 2000). Shh and twhh are also expressed in the RPE and in amacrine cells (Shkumatava et al, 2004), and the Hh signal from these sources is essential for the progression of photoreceptor differentiation. Demonstration of expression of the receptor complex has been difficult (Shkumatava et al, 2004), although our laboratory has detected expression of ptc2 within zebrafish embryo eyes, with tentative localization to retinal progenitor cells .…”

Section: Extrinsic Factorsmentioning

confidence: 99%

“…Shh and twhh are also expressed in the RPE and in amacrine cells (Shkumatava et al, 2004), and the Hh signal from these sources is essential for the progression of photoreceptor differentiation. Demonstration of expression of the receptor complex has been difficult (Shkumatava et al, 2004), although our laboratory has detected expression of ptc2 within zebrafish embryo eyes, with tentative localization to retinal progenitor cells .…”

Section: Extrinsic Factorsmentioning

confidence: 99%

“…However, there is also evidence that the Hh signal arising from amacrine cells may be the key signal for promoting photoreceptor differentiation. The evidence for this conclusion comes from a highly creative experiment (Shkumatava et al, 2004). Mosaic embryos were generated, consisting of a combination of syu −/− cells and wild-type shh:GFP cells.…”

Section: Extrinsic Factorsmentioning

confidence: 99%

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Neurogenesis in the Fish Retina

Stenkamp

2007

International Review of Cytology

122

136

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The retinas of teleost fish have long been of interest to developmental neurobiologists for their persistent plasticity during growth, life history changes, and response to injury. Because the vertebrate retina is a highly conserved tissue, the study of persistent plasticity in teleosts has provided insights into mechanisms for postembryonic retinal neurogenesis in mammals. In addition, in the past 10 years there has been an explosion in the use of teleost fish-zebrafish (Danio rerio) in particular-to understand the mechanisms of embryonic retinal neurogenesis in a model vertebrate with genetic resources. This review summarizes the key features of teleost retinal neurogenesis that make it a productive and interesting experimental system, and focuses on the contributions to our knowledge of retinal neurogenesis that uniquely required or significantly benefited from the use of a fish model system.

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Developmental mechanisms for retinal degeneration in the blind cavefish Astyanax mexicanus

Alunni¹,

Menuet²,

Candal³

et al. 2007

J of Comparative Neurology

100

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The sighted surface-dwelling (surface fish, SF) and the blind cave-living (cavefish, CF) forms of Astyanax mexicanus offer a unique opportunity to study the evolutionary changes in developmental mechanisms that lead to retinal degeneration. Previous data have shown the role of increased midline Sonic Hedgehog (Shh) signalling in cavefish eye degeneration (Yamamoto et al. [2004] Nature 431:844-847). Here, we have compared the major steps of eye development in SF and CF between 14 hours and 5 days of development. We have analyzed cell proliferation through PCNA and phospho-histone H3 staining and apoptosis through TUNEL and live LysoTracker analysis. We have assessed the expression of the major eye development signalling factors Shh and Fgf8, and the eye patterning genes Pax6, Lhx2, Lhx9, and Vax1, together with the differentiation marker GAD65. We show that eye development is retarded in CF and that cell proliferation in CF retina is proportionately similar to SF during early development, yet the retina degenerates after massive apoptosis in the lens and widespread cell death throughout the neuroretina. Moreover, and surprisingly, the signalling, patterning, and differentiation processes leading to the establishment of retinal layers and cell types happen almost normally in CF, although some signs of disorganization, slight heterochronies, and a lack of expression gradients are observable. Our data demonstrate that the evolutionary process of eye degeneration in the blind CF does not occur because of patterning defects of the retina and are consistent with the proposed scenario in which the trigger for eye degeneration in CF is lens apoptosis.

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Sonic hedgehog, secreted by amacrine cells, acts as a short-range signal to direct differentiation and lamination in the zebrafish retina

Abstract: SummarySonic hedgehog, secreted by amacrine cells, acts as a short-range signal to direct differentiation and lamination in the zebrafish retina

Cited by 137 publications

References 32 publications

Zebrafish: A model system for the study of eye genetics

Zebrafish: A model system for the study of eye genetics

Neurogenesis in the Fish Retina

Developmental mechanisms for retinal degeneration in the blind cavefish Astyanax mexicanus

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