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At least 19 recordsLinked to original sources
PubMed1993

Rod-opsin immunoreaction in the pineal organ of the pigmented mouse does not indicate the presence of a functional photopigment.

The aim of the present study was to characterize the rod-opsin immunoreaction in the mammalian pineal organ. Pigmented mice (strain C57BL) were selected as the animal model. Immunocytochemical investigations involving the use of highly specific polyclonal and monoclonal antibodies against bovine rod-opsin (the apoprotein of the photopigment rhodopsin) showed that approximately 25% of all pinealocytes were rod-opsin immunoreactive. Immunoblotting techniques revealed three protein bands of approximately 40, 75, and 110 kDa; these were detected by the monoclonal antibody and the polyclonal antiserum in retinal and pineal extracts. These protein bands presumably represented the monomeric, dimeric and trimeric forms of rod-opsin. The amount of rod-opsin in retina and pineal organ was quantified by means of an enzyme-linked immunosorbent assay. This yielded 570 +/- 30 pmoles rod-opsin per eye and 0.3 +/- 0.05 pmoles rod-opsin per pineal organ. High pressure liquid chromatography analysis of whole eye extracts demonstrated the chromophoric group of the photopigment rhodopsin, 11-cis retinal, and its isomer, all-trans-retinal. A shift from 11-cis retinal to all-trans-retinal was found upon light adaptation. No retinals were detected in the pineal organ. Autoradiographic investigations showed that 3H-retinol, intraperitoneally injected into the animals, was incorporated into the outer and inner segments of retinal photoreceptors, but not into the pineal organ. It is concluded that the mouse pineal organ contains the authentic apoprotein of rhodopsin but that it lacks retinal derivatives as essential components of all known vertebrate photopigments.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Ontogenetic development of S-antigen- and rod-opsin immunoreactions in retinal and pineal photoreceptors of Xenopus laevis in relation to the onset of melatonin-dependent color-change mechanisms.

In Xenopus laevis Daud., the ontogenetic occurrence of two photoreceptor-specific proteins, S-antigen and rod-opsin, was investigated and correlated to the maturation of the neurohormonal effector system involved in melatonin-dependent color-change mechanisms. Tadpoles ranging from stage 12 to 57 (Nieuwkoop and Faber 1956) were fixed in Zamboni's or Bouin's solution. Frozen or paraffin sections of either total heads or dissected brains and eyes were prepared and treated with highly specific antisera against S-antigen and rod-opsin. In the retina, immunoreactive S-antigen and rod-opsin were first demonstrated in a few centrally located photoreceptors at stage 37/38. Photoreceptors of the peripheral (iridical) portions of the retina gradually became immunoreactive during further development. As in the retina, the first S-antigen-immunoreactive photoreceptors in the pineal complex appeared at stage 37/38. At this and all later stages investigated rod-opsin immunoreactivity was restricted to a few dot-like structures resembling developing pineal outer and inner segments. In most animals rod-opsin immunoreactivity was completely absent from the pineal complex. The analysis of retinal proteins with the immunoblotting technique (Western blot) revealed that the S-antigen antibody bound to a 48-kDa protein and the rod-opsin antibody to a 38-kDa protein. The body lightening reaction was determined with the aid of the melanophore index in larvae fixed in light or darkness, respectively. Aggregation of melanophore melanosomes in darkness (the melatonin-dependent primary chromatic response) first occurred at stage 37/38 when melanophores started to differentiate and became pigmented. These results indicate that in Xenopus laevis (i) the molecular mechanisms of photoreception develop simultaneously in retina and pineal complex; (ii) most pineal photoreceptors differ from retinal rods in that they contain immunoreactive S-antigen but essentially no immunoreactive rod-opsin; and (iii) the differentiation of phototransduction processes coincides with the onset of melatonin-dependent photoneuroendocrine regulation of color-change mechanisms.

Animals↗
PubMed1995

The appearance of rod opsin during monkey retinal development.

PURPOSE: To determine the temporal and spatial pattern of rod opsin appearance in Macaca monkey retina. METHODS: Frozen sections from fetal day (Fd) 55 to adulthood (birth = Fd168) containing the entire horizontal meridian were stained using Rho4D2 monoclonal antiserum visualized with immunofluorescent labeling. At Fd66, Fd79, and Fd89, retinal samples taken at known eccentricities were studied from the opposite eye using standard electron microscope methods. RESULTS: Rod opsin was detected at Fd66 in or near the fovea, and a second focus appeared at Fd75 to Fd77 near the optic disc in the nasal rod ring. The earliest opsin appeared in the apical stubs, which resembled the apical connecting cilium in the electron microscope. Staining of the entire cell body membrane, including the synaptic spherule, was present 4 to 7 days later. Opsin expression had a nasal bias with rods at the nasal ora labeled at Fd140, whereas temporal ora was not labeled until Fd155. Cell body labeling disappeared by Fd132 across central retina but persisted into the first postnatal year in far peripheral retina. Outer segment (OS) length measurements showed that rods in the rod ring had the longest OS between Fd115 and postnatal week 9. Rod OS at all retinal eccentricites continued to elongate between 11 months of age and adulthood. CONCLUSIONS: Rod opsin expression follows a foveal-to-peripheral gradient beginning at Fd66 and ending near birth. Rod opsin is detected first in the connecting cilium and slightly later in the entire cell membrane, and then cell membrane labeling disappears as the heavily labeled OS elongates. Although the first OS appear on rods near the fovea, these OS still are short at birth and do not reach adult length until after 2 years of age. The longest OS at birth are found on rods at the rod ring, suggesting that this region could have higher scotopic sensitivity than central retina at birth.

Aging↗
PubMed1990

Immunocytochemical localization of serotonin and photoreceptor-specific proteins (rod-opsin, S-antigen) in the pineal complex of the river lamprey, Lampetra japonica, with special reference to photoneuroendocrine cells.

The pineal complex of the river lamprey, Lampetra japonica, was examined by means of immunocytochemistry with antisera against serotonin, the precursor of melatonin, and two photoreceptor proteins, rod-opsin (the apoprotein of the photopigment rhodopsin) and S-antigen. Serotonin-immunoreactive cells were observed in both the pineal and the parapineal organ. The proximal portion of the pineal organ (atrium) comprised numerous serotonin-immunoreactive cells displaying spherical somata. In the distal end-vesicle of the pineal organ, the serotonin-immunoreactive elements resembled photoreceptors in their size and shape. These cells projecting into the pineal lumen and toward the basal lamina were especially conspicuous in the ventral portion of the end-vesicle. In addition, single serotonin-immunoreactive nerve cells were found in this location. Retinal photoreceptors were never seen to contain immunoreactive serotonin; amacrine cells were the only retinal elements exhibiting serotonin immunoreaction. Strong S-antigen immunoreactivity was found in numerous photoreceptors located in the pineal end-vesicle. In contrast, the S-antigen immunoreactivity was weak in the spherical cells of the atrium. Thus, the pattern of S-antigen immunoreactivity was roughly opposite to that of serotonin. Similar findings were obtained in the parapineal organ. The rod-opsin immunoreaction was restricted to the outer segments of photoreceptors in the pineal end-vesicle and parapineal organ. No rod-opsin++ immunoreactive outer segments occurred in the proximal portion of the atrium. Double immunostaining was employed to investigate whether immunoreactive opsin and serotonin are colocalized in one and the same cell. This approach revealed that (i) most of the rod-opsin-immunoreactive outer segments in the end-vesicle belonged to serotonin-immunonegative photoreceptors; (ii) nearly all serotonin-immunoreactive cells in the end-vesicle bore short rod-opsin-immunoreactive outer segments protruding into the pineal lumen; and (iii) the spherical serotonin-immunoreactive cells in the pineal stalk lacked rod-opsin immunoreaction and an outer segment. These results support the concept that multiple cell lines of the photoreceptor type exist in the pineal complex at an early evolutionary stage.

Animals↗
PubMed1992

Immunocytochemical demonstration of rod-opsin, S-antigen, and neuron-specific proteins in the human pineal gland.

The aim of this study was to examine whether rod-opsin and S-antigen immunoreactions were present in the pineal organ of adult man and how these immunoreactions were correlated with neuronal markers, e.g., synaptophysin, and neurofilaments L, H and M. Three perfusion-fixed epithalamic regions including the pineal organ and five pineal glands obtained at routine autopsy were used. The specimens were taken from female or male patients, 25 to 85 years of age. All immunoreactions were performed using highly specific, well-characterized antibodies. Rod-opsin and S-antigen-immunoreactive pinealocytes occurred in all pineal organs investigated; however, the immunoreaction was restricted to small subpopulations of pinealocytes (rod-opsin immunoreaction: approximately 3%-5%; S-antigen immunoreaction: approximately 5%-10% of the total population). In contrast, immunoreactions for synaptophysin and neurofilaments M and H were present in numerous pinealocytes. Immunoreactivity for neurofilament L was not found. These data suggest that the cellular composition of the human pineal organ is heterogeneous. Moreover, the presence of rod-opsin and S-antigen immunoreactions in the human pineal organ indicates that it may be affected by autoimmune retinal diseases that are provoked by antibodies against these proteins, as is the case in rodents and non-human primates.

Adult↗
PubMed1992

Rod opsin cDNA sequence from the sand goby (Pomatoschistus minutus) compared with those of other vertebrates.

The absorbance spectra of rods from the sand goby were measured by using microspectrophotometry. Analysis of the averaged spectra shows that the rod visual pigment has a maximum absorbance (lambda max) at approximately 501 nm. A sand goby retinal cDNA library was constructed and then screened with a partial sand goby rod opsin clone obtained by the polymerase chain reaction (PCR). The screening of the library yielded a full length rod opsin clone. The cDNA sequence and deduced amino acid sequence of this clone are compared with those of other vertebrate rod opsins.

Amino Acid Sequence↗
PubMed1989

Differentiation in medulloblastomas: correlation between the immunocytochemical demonstration of photoreceptor markers (S-antigen, rod-opsin) and the survival rate in 66 patients.

Biopsy specimens of 66 medulloblastomas were investigated by means of S-antigen and rod-opsin immunocytochemistry. The patients were operated between 1969 and 1988 and the medical records were retrospectively evaluated to correlate the immunocytochemical features of the tumors to the course of the disease. S-antigen- and rod-opsin-immunoreactive tumor cells were found in 19 out of 66 cases. Since in the normal non-neoplastic state immunoreactive S-antigen and rod-opsin are restricted to retinal photoreceptors and a class of pinealocytes derived from photoreceptor cells, the occurrence of these proteins in certain tumor cells of medulloblastomas suggests a differentiation of these cells along the photoreceptor cell lineage and allows the identification of a special subtype of medulloblastoma displaying photoreceptor-specific characteristics. This subtype appears to be closely related to retinoblastomas and pineal cell tumors. The incidence of this subtype corresponds to approximately 30% of all medulloblastomas. Correlation between the demonstration of immunoreactive S-antigen and rod-opsin and the course of the disease revealed a 10-year survival rate of 50.6% for patients with medulloblastomas displaying photoreceptor-specific characteristics and maximally 11% for patients suffering from medulloblastomas devoid of these markers. Although the statistical evaluation does not provide a significant result, the estimated P-value of 0.085 indicates a distinct trend toward a better prognosis for patients suffering from medulloblastomas with photoreceptor-specific features. The validity of this trend needs to be proven in further studies with a greater number of patients.

Adolescent↗
PubMed1991

Tissue-specific and developmental regulation of rod opsin chimeric genes in transgenic mice.

Chimeric gene fusions between 4.4 kb of rod opsin 5' flanking sequence fused to a diphtheria toxin gene and 4.4 kb or 500 bp of rod opsin 5' flanking sequence fused to the E. coli IacZ gene were used to generate transgenic mice for analysis of cell type-specific expression and temporal and spatial distribution of reporter gene product during retinal development. Opsin-diphtheria toxin transgene expression evoked photoreceptor-specific cell death. The 4.4 kb opsin-IacZ transgene followed temporal and spatial gradients of expression that approximate opsin expression. The 500 bp opsin fragment targeted expression to photoreceptors, but expression was weaker and nonuniform, suggesting that elements located upstream may be required for enhanced and uniform spatial expression.

Animals↗
PubMed2000

Molecular cloning of fresh water and deep-sea rod opsin genes from Japanese eel Anguilla japonica and expressional analyses during sexual maturation.

We have determined the complete cDNA sequences of fresh water rod opsin gene (fwo) and deep-sea rod opsin gene (dso) from Japanese eel Anguilla japonica. The cDNA clones of fwo and dso consisted of 1437 and 1497 nucleotides, respectively. The predicted opsins of both genes consisted of 352 amino acid residues. Southern blot and PCR analyses of genomic DNA indicated that the Japanese eel genome contains only one fwo and one dso and they are intronless. Quantitative RT-PCR analyses revealed that the expression of fwo decreases with sexual maturation while that of dso increases.

Anguilla↗
PubMed1990

S-antigen and rod-opsin immunoreactions in midline brain neoplasms of transgenic mice: similarities to pineal cell tumors and certain medulloblastomas in man.

Transgenic mice expressing the large T-antigen of the simian virus 40 (SV 40) under the control of 1) the enhancer of Moloney murine sarcoma virus (MSV) and 2) the SV 40 promoter develop undifferentiated neuroectodermal tumors located in the midline of the dorsal brain surface, abnormalities in lens fiber differentiation and retinal dysplasia. In this study the brain neoplasms of six adult animals and the brain of one 11-day old mouse were examined by conventional histology and immunocytochemical demonstration of S-antigen, rod-opsin, neuron-specific enolase, neurofilaments (160 and 200 kDa) and glial fibrillary acidic protein. According to histologic criteria the neoplasms were characterized as "primitive" neuroectodermal tumors composed mainly of small cells with scanty and ill-defined cytoplasm. Neoplastic cells displaying immunoreactive S-antigen were found in five brain tumors; three of these tumors also contained a limited number of rod-opsin immunoreactive neoplastic cells. Some tumor cells had neurite-like processes containing immunoreactive neurofilament (200 kDa). No pathologic lesions were found in the brain of the 11-day old animal. Tumors in transgenic mice may resemble pineal cell tumors and a special subtype of medulloblastoma in man. These neoplasms contain S-antigen immunoreactive and also rod-opsin immunoreactive tumors cells in certain cases. The findings suggest that transgenic mice expressing the large T-antigen of SV 40 may become a valuable animal model for analysing the origin, histogenesis and development of primitive neuroectodermal tumors with photoreceptor-like features (pineal cell tumors and certain medulloblastomas).

Animals↗
PubMed1995

Cloning and characterization of rod opsin cDNA from the Old World monkey, Macaca fascicularis.

PURPOSE: Opsin sequences from different phyla have been compared to examine the structural and functional regions of this molecule and to assess the molecular evolution of genes in the animal kingdom. Of all the sequences reported, there is only one primate sequence (human) for rod opsin. To extend our knowledge of the primate family of opsins, the authors cloned and characterized the opsin cDNA for the Old World monkey Macaca fascicularis and determined its position in the phylogenetic tree of the opsin gene family. METHODS: A fragment of the monkey opsin cDNA was generated using specific primers and the polymerase chain reaction. This fragment was then used as a probe to isolate several cDNA clones from a M. fascicularis retinal cDNA library. The nucleotide sequence of monkey opsin was determined and translated into an amino acid sequence. The amino acid sequences of opsins from a variety of organisms ranging from mollusks, arthropods, and vertebrates, including monkey, were then compared to identify highly conserved amino acid residues and to construct a phylogenetic tree of the rod opsins. RESULTS: The monkey has a single major 2.2-kb transcript for opsin and minor transcripts of 1.5, 4.8, and 8.9 kb. The major transcript is highly abundant in the monkey retina and is localized to the inner segments of rod photoreceptor cells, typical of opsin mRNAs in other organisms. The sequence of monkey opsin closely resembles the human sequence at the nucleotide and the amino acid levels, with the latter having only 7 differences out of 348 residues. Comparison of the monkey sequence with the amino acid sequences from diverse organisms shows that all opsins share only 34 conserved amino acids, with the highest concentration of these residues occurring in the first cytoplasmic loop of rhodopsin. A hypothetical phylogenetic tree of the opsins suggests that both human and monkey opsin shared an ancestral gene with the mammalian Order Carnivora. CONCLUSION: The opsins of man and Old World monkeys have diverged little from the time they shared a common ancestor. Comparison of opsins from diverse phyla, however, shows that only 34 residues have been conserved. These conserved residues are likely to be important in the structure and function of rhodopsin.

Amino Acid Sequence↗
PubMed1998

Switch in rod opsin gene expression in the European eel, Anguilla anguilla (L.).

The rod photoreceptors of the European eel, Anguilla anguilla (L.), alter their wavelength of maximum sensitivity (lambda max) from c.a. 523 nm to c.a. 482 nm at maturation, a switch involving the synthesis of a new visual pigment protein (opsin) that is inserted into the outer segments of existing rods. We artificially induced the switch in rod opsin production by the administration of hormones, and monitored the switch at the level of mRNA accumulation using radiolabelled oligonuleotides that hybridized differently to the two forms of eel rod opsin. The production of the deep-sea form of rod opsin was detected 6 h after the first hormone injection, and the switch in rod opsin expression was complete within four weeks, at which time only the mRNA for the deep-sea opsin was detectable in the retinal cells. It is suggested that this system could be used as a tractable model for studying the regulatory control of opsin gene expression.

Anguilla↗
PubMed1997

Mechanisms of wavelength tuning in the rod opsins of deep-sea fishes.

The main object of this study was to investigate the molecular basis for changes in the spectral sensitivity of the visual pigments of deep-sea fishes. The four teleost species studied, Hoplostethus mediterraneus, Cataetyx laticeps, Gonostoma elongatum and Histiobranchus bathybius, are phylogenetically distant from each other and live at depths ranging from 500 to almost 5000 m. A single fragment of the intronless rod opsin gene was PCR-amplified from each fish and sequenced. The wavelength of peak sensitivity for the rod visual pigments of the four deep-sea species varies from 483 nm in H. mediterraneus and G. elongatum to 468 nm in C. laticeps. Six amino acids at sites on the inner face of the chromophore-binding pocket formed by the seven transmembrane a-helices are identified as candidates for spectral tuning. Substitutions at these sites involve either a change of charge, or a gain or loss of a hydroxyl group. Two of these, at positions 83 and 292, are consistently substituted in the visual pigments of all four species and are likely to be responsible for the shortwave sensitivity of the pigments. Shifts to wavelengths shorter than 480 nm may involve substitution at one or more of the remaining four sites. None of the modifications found in the derived sequences of these opsins suggest functional adaptations, such as increased content of hydroxyl-bearing or proline residues, to resist denaturation by the elevated hydrostatic pressures of the deep sea. Phylogenetic evidence for the duplication of the rod opsin gene in the Anguilliform lineage is presented.

Adaptation, Physiological↗
PubMed1992

Abnormal dark adaptation kinetics in autosomal dominant sector retinitis pigmentosa due to rod opsin mutation.

The time course of dark adaptation was measured in 10 subjects from three families with autosomal dominant sector retinitis pigmentosa (RP) due to mutations in the first exon of the rod opsin gene. In each subject cone adaptation and the early part of the recovery of rod sensitivity followed the normal time course, but the later phase of rod adaptation was markedly prolonged. The recovery of rod sensitivity is much slower than that reported in any other outer retinal dystrophy. Using a model based upon primate data of rod outer segment length and turnover, we have calculated that the delayed phase of the recovery of rod sensitivity in the RP patients tested following strong light adaptation could be due in part to formation of new disc membrane with its normal concentration of rhodopsin rather than in situ regeneration of photopigment.

Adolescent↗
PubMed1994

Nucleotide sequence of the canine rod-opsin-encoding gene.

The major parts of two canine rod-specific opsin (Ops) transcripts have been cloned by polymerase chain reaction from retinal mRNA. Both transcripts are derived from the same gene. The 5' leader sequence of the transcripts was cloned from canine peripheral blood DNA. The transcripts code for a protein of 348 amino acids (aa), M(r) 38,962 (prior to any protein modification). The aa sequence suggests that in common with other sequenced Ops, canine rod Ops contains seven transmembrane domains, and residues believed essential for retinal pigment binding and for palmitate binding are conserved in the canine protein. Northern blotting using the central part of the ops gene as probe suggested that mature transcripts of three different sizes (about 1900, 2600 and 5500 bases) were found in retina. Of these, the 2600-base transcript was the most abundant. RACE cloning of the 3' end of ops showed that at least two of these size classes originate from differential transcript termination.

Amino Acid Sequence↗
PubMed1997

A second type of rod opsin cDNA from the common carp (Cyprinus carpio).

A second type of rhodopsin cDNA from carp (cRh-II) shared 97.2% polynucleotide identity with the previously reported cRh-I. The deduced amino acid sequences of cRh-I and cRh-II exhibited 98.6% identity. The key difference between these two types of cRh is that valine at position 169 of cRh-I was replaced by glutamic acid in cRh-II. Southern blot analysis of genomic DNA showed that there were two types of cRh gene. These two rod opsin genes were proven to be expressed in carp retinas by using RT-PCR with type-specific primers.

Amino Acid Sequence↗
PubMed1993

Presence and foveal enrichment of rod opsin in the "all cone" retina of the American chameleon.

The retinal photoreceptors of the eye of the American chameleon, Anolis carolinensis, have been considered to be exclusively cones. Its retina is unusual for possessing two foveas (areas associated with heightened visual acuity), with the major, central fovea deeply incised and very densely packed with photoreceptors. Immunoblotting and light- and electron microscopic-immunocytochemistry, using several opsin monoclonal antibodies previously found specific for rods, demonstrated the presence and localization of this protein in the Anolis retina. This visual pigment appears sparsely in a subpopulation of photoreceptors in the periphery but overwhelmingly in the central fovea. Complementary results with cone-specific antibody and lectin binding corroborated this spatial organization. These results, as well as those with geckos, suggest that photoreceptor morphology is not an accurate guide among the lacertilians to visual pigment content, and that this phylogenetic grouping may constitute a crossroads in vertebrate photoreceptor evolution.

Animals↗
PubMed1997

Molecular cloning of a rod opsin cDNA from the skate retina.

Skates (Raja erinacea and R. ocellata) are among the few animals that have an exclusively rod retina. However, skate rods are unusual in that they are capable of adapting to extremely high levels of illumination that initially saturate the rod photocurrent. This adaptive process restores the ability of the visual cells to respond to incremental photic stimuli and enables them to function under ambient conditions that are subserved by the cone mechanism in mixed (rod/cone) retinae. As a first step towards exploring the molecular basis of visual adaptation in the skate retina, we have cloned and analyzed the opsin cDNA from a skate retina library. The cDNA codes for a protein 354 amino acids (aa) long and 39.7 kDa predicted molecular mass, and labels a single abundant transcript of 1.7 kb in retinal RNA. Amino acid alignments and a parsimony analysis of nucleotide alignments show the skate opsin to be homologous to other rod opsins. An analysis of the aa sequence reveals a high degree of conservation of those residues thought to be important for most aspects of rhodopsin function. However, a few critical aa replacements may indicate alterations in the interactions of skate rhodopsin with other proteins in the phototransduction cascade. In particular, replacements of Glu150 with serine and Cys323 with leucine are in cytoplasmic domains thought to interact with transducin and rhodopsin kinase. The latter change eliminates one of the conserved acylation sites in the carboxyl terminal tail. These substitutions increase the similarity of the cytoplasmic domains of skate opsin to those of blue-sensitive visual pigments.

Amino Acid Sequence↗