Stenkamp, D.L., Cunningham, L.L., Raymond, P.A. & Gonzalez-Fernandez, F. Novel expression pattern of interphotoreceptor retinoid-binding protein (IRBP) in the adult and developing zebrafish retina and RPE. Mol. Vis. 4, 26

Department of Anatomy and Cell Biology, University of Michigan, Ann Arbor, MI, USA.
Molecular vision (Impact Factor: 1.99). 01/1999; 4:26.
Source: PubMed


Interactions between the neural retina and retinal pigment epithelium (RPE) are mediated by the interphotoreceptor matrix (IPM). The transport of retinoids across the IPM is mediated by interphotoreceptor retinoid-binding protein (IRBP). To explore the possibility that IRBP is important during retinal development, we examined its spatiotemporal expression pattern in embryonic zebrafish.
IRBP mRNA expression was examined using RT-PCR and in situ hybridization. IRBP was localized using antiserum against recombinant zebrafish IRBP. IRBP synthesis and secretion were studied by in vitro metabolic labeling of retinas and RPE-eyecups.
IRBP mRNA was first observed in the pineal at 24 hours post-fertilization (hpf) and in the ventral retina at 50 hpf. Immunoreactive IRBP was first observed at 72 hpf. Remarkably, IRBP was expressed not only by photoreceptors but also by the adult and embryonic RPE. In embryos, expression in both retina and RPE began in a ventronasal patch and spread to involve the entire eye. In general, early IRBP expression was dominated by photoreceptors, but then RPE expression spread beyond the limit of photoreceptor expression. Double in situ hybridizations suggests that cones express IRBP mRNA before they express a specific opsin, while rods may express rod opsin prior to IRBP.
The temporal and spatial patterns of IRBP expression by the RPE and retina are consistent with a role in retinal development and suggest coordination of RPE and photoreceptor differentiation.

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    • "The irbp gene is expressed early during rodent retinal development and is upregulated before the expression of opsins [40]. The temporal and spatial expression patterns of the zfirbp gene in zebrafish are consistent with a role in retinal development and suggest coordination of retinal pigment epithelium and photoreceptor differentiation [41]. There has been so far no evidence that temperature can play a role in the regulation of expression of this gene. "
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    • "bernacchii sequences available, only four failed to align to a unigene sequence. Two of these sequences form interphotoreceptor retinoid-binding protein (IRBP), a protein that accumulates in the subretinal space and facilitates exchanges during the “visual cycle” [36]. Due to the high degree of specificity to the visual process, it is unlikely that this product would be found in the liver, gill or brain tissues that were sequenced in this effort. "
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    BMC Genomics 11/2013; 14(1):805. DOI:10.1186/1471-2164-14-805 · 3.99 Impact Factor
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    • "In the chicken pineal gland, the mRNA encoding the photopigment Pinopsin shows a rhythm that is dependent upon activation by light [62]. In zebrafish, interphotoreceptor retinoid-binding protein (irbp) mRNA expression is circadian-regulated, while and IRBP protein levels are constant [37,63]. In the case of IRBP, it is proposed that the higher expression of mRNA during the day is necessary to maintain the constant levels of protein, as protein turnover is much higher during the day than during the night [37,63]. "
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