Reprint of: The ciliary marginal zone (CMZ) in development and regeneration of the vertebrate eye

Fischer, Andy J.; Bosse, Jennifer L.; El‐Hodiri, Heithem M.

doi:10.1016/j.exer.2014.04.019

Cited by 23 publications

(15 citation statements)

References 57 publications

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“…Thus, the Pacific hagfish eyes appear degenerate (rudimentary and diminutive) but are not overtly degenerating over ontogeny. Observing larger eyes in larger hagfish was reminiscent of fishes' eye growth that continues into adulthood, supported by proliferating cells at the outer edges of the mature retina known as the ciliary marginal zone (CMZ) [11][12][13]. We observed that hagfish eyes possess a comparable region and propose that it contributes to sustained eye growth.…”

Section: (B) Hagfish Eyes Grow Over Ontogeny Perhaps Via Pax6-expressmentioning

confidence: 96%

Vertebrate features revealed in the rudimentary eye of the Pacific hagfish (Eptatretus stoutii)

Dong

Allison

2021

Proc. R. Soc. B.

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Hagfish eyes are markedly basic compared to the eyes of other vertebrates, lacking a pigmented epithelium, a lens and a retinal architecture built of three cell layers: the photoreceptors, interneurons and ganglion cells. Concomitant with hagfish belonging to the earliest-branching vertebrate group (the jawless Agnathans), this lack of derived characters has prompted competing interpretations that hagfish eyes represent either a transitional form in the early evolution of vertebrate vision, or a regression from a previously elaborate organ. Here, we show the hagfish retina is not extensively degenerating during its ontogeny, but instead grows throughout life via a recognizable PAX6 + ciliary marginal zone. The retina has a distinct layer of photoreceptor cells that appear to homogeneously express a single opsin of the RH1 rod opsin class. The epithelium that encompasses these photoreceptors is striking because it lacks the melanin pigment that is universally associated with animal vision; notwithstanding, we suggest this epithelium is a homologue of gnathosome retinal pigment epithelium (RPE) based on its robust expression of RPE65 and its engulfment of photoreceptor outer segments. We infer that the hagfish retina is not entirely rudimentary in its wiring, despite lacking a morphologically distinct layer of interneurons: multiple populations of cells exist in the hagfish inner retina and subsets of these express markers of vertebrate retinal interneurons. Overall, these data clarify Agnathan retinal homologies, reveal characters that now appear to be ubiquitous across the eyes of vertebrates, and refine interpretations of early vertebrate visual system evolution.

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Section: (B) Hagfish Eyes Grow Over Ontogeny Perhaps Via Pax6-expressmentioning

confidence: 96%

Vertebrate features revealed in the rudimentary eye of the Pacific hagfish (Eptatretus stoutii)

Dong

Allison

2021

Proc. R. Soc. B.

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“…PAX6 expression is most concentrated at the tip of the retinal marginal zone (Fig. 2B-E), suggesting that not only do these cells appear undifferentiated by morphology, but that they also express transcripts related to the maintenance of a multipotent cell state (Fischer et al, 2014;Marquardt et al, 2001).…”

Section: Hagfish Eyes Grow Over Ontogeny Perhaps Via Pax6-expressing mentioning

confidence: 99%

“…In gnathostomes, the CMZ expresses PAX6 (Fischer et al, 2014). An ortholog of PAX6 highly conserved with that of other vertebrates, was found to be expressed in the hagfish retina.…”

Section: Hagfish Eyes Grow Over Ontogeny Perhaps Via Pax6-expressing mentioning

confidence: 99%

Vertebrate features revealed in the rudimentary eye of the Pacific hagfish (Eptatretus stoutii)

Dong

Allison

2020

Preprint

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SUMMARYHagfish eyes are markedly basic compared to the eyes of other vertebrates, lacking a pigmented epithelium, a lens, and a retinal architecture built of three cell layers – the photoreceptors, interneurons & ganglion cells. Concomitant with hagfish belonging to the earliest-branching vertebrate group (the jawless Agnathans), this lack of derived characters has prompted competing interpretations that hagfish eyes represent either a transitional form in the early evolution of vertebrate vision, or a regression from a previously elaborate organ. Here we show the hagfish retina is not extensively degenerating during its ontogeny, but instead grows throughout life via a recognizable Pax6+ ciliary marginal zone. The retina has a distinct layer of photoreceptor cells that appear to homogeneously express a single opsin of the rh1 rod opsin class. The epithelium that encompasses these photoreceptors is striking because it lacks the melanin pigment that is universally associated with animal vision; notwithstanding, we suggest this epithelium is a homolog of gnathosome Retinal Pigment Epithelium (RPE) based on its robust expression of RPE65 and its engulfment of photoreceptor outer segments. We infer that the hagfish retina is not entirely rudimentary in its wiring, despite lacking a morphologically distinct layer of interneurons: multiple populations of cells exist in the hagfish inner retina that differentially express markers of vertebrate retinal interneurons. Overall, these data clarify Agnathan retinal homologies, reveal characters that now appear to be ubiquitous across the eyes of vertebrates, and refine interpretations of early vertebrate visual system evolution.HIGHLIGHTSHagfish eyes are degenerate but not degenerating, i.e. rudimentary but growingRetinal interneurons discovered implying ancestral hagfish had derived retinas & visionDespite lacking pigment, a Retinal Pigmented Epithelium homolog functions in hagfishRevised synapomorphies illuminate the dimly lit origins of vertebrate eye evolutionGRAPHICAL ABSTRACT

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“…However, a number of different cellular sources of RSCs/PCs have been identified in the adult mammalian eye, raising the possibility of autologous transplantation if these cells could be expanded and induced to differentiate into desirable retinal cell types. These include pigmented cells in ciliary body, iris pigment epithelium (IPE), and retinal pigment epithelium (RPE), and Müller cells within the retina (7)(8)(9)(10)(11)(12). Therefore, this review provides an update on the nature and origin of these different niches for RSCs/PCs found within the eye.…”

Section: Introductionmentioning

confidence: 99%

Adult Stem Cells, Tools for Repairing the Retina

Aladdad

Kador

2019

Curr Ophthalmol Rep

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Purpose: Retinal degenerative diseases lead to the death of retinal neurons causing visual impairment and blindness. In lower order vertebrates, the retina and its surrounding tissue contain stem cell niches capable of regenerating damaged tissue. Here we examine these niches and review their capacity to be used as retinal stem/progenitor cells (RSC/RPCs) for retinal repair. Recent Findings: Exogenous factors can control the in vitro activation of RSCs/PCs found in several niches within the adult eye including cells in the ciliary margin, the retinal pigment epithelium, iris pigment epithelium as well as the inducement of Müller and amacrine cells within the neural retina itself. Recently, factors have been identified for the activation of adult mammalian Müller cells to a RPC state in vivo. Summary: Whereas cell transplantation still holds potential for retinal repair, activation of the dormant native regeneration process may lead to a more successful process including greater integration efficiency and proper synaptic targeting.

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Reprint of: The ciliary marginal zone (CMZ) in development and regeneration of the vertebrate eye

Cited by 23 publications

References 57 publications

Vertebrate features revealed in the rudimentary eye of the Pacific hagfish (Eptatretus stoutii)

Vertebrate features revealed in the rudimentary eye of the Pacific hagfish (Eptatretus stoutii)

Vertebrate features revealed in the rudimentary eye of the Pacific hagfish (Eptatretus stoutii)

Adult Stem Cells, Tools for Repairing the Retina

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