Disease relevance of OPN1LW

• The results of previous immunocytochemical and electrophysiological studies of retinas of rd (retinal degeneration) chicks suggest that the iodopsin cone visual pigment may be defective in this mutant [1].

High impact information on OPN1LW

• Circadian regulation of iodopsin gene expression in embryonic photoreceptors in retinal cell culture [2].
• In this study, we show that mRNA for the red-sensitive cone pigment, iodopsin, fluctuates with a circadian rhythm in chicken retina [2].
• The primary structures of chicken red (iodopsin) and rhodopsin have been determined previously [3].
• We have found that the amino acid sequence of P521 deduced from the cDNA was very similar to that of iodopsin [4].
• Although bathoiodopsin produced at the temperature of liquid nitrogen or helium reverted to the original pigment (iodopsin) on warming (above -170 degrees C), the bathoiodopsin produced at physiological temperature decayed to all-trans-retinal and R-photopsin (the protein moiety of iodopsin) presumably through several intermediates [5].

Biological context of OPN1LW

• The amino acid sequence has been determined for the carboxyl-terminal 41 amino acids of chicken red-sensitive cone pigment, iodopsin [6].
• Phosphorylation of iodopsin, chicken red-sensitive cone visual pigment [6].
• These observations suggest that the retinal binding site of iodopsin is located near the protein surface [7].
• Northern cDNA sequence and western analyses were used to study rd/rd iodopsin. cDNAs encoding rd/rd iodopsin were obtained by screening an rd/rd cDNA retinal expression library and by reverse transcription PCR [1].
• Since antibodies to iodopsin and rhodopsin stained different types of photoreceptors in the intact chick retina, it will be possible to analyze cell lineage of rods and cones in vitro by use of these antibodies [8].

Anatomical context of OPN1LW

• In the differentiating cones of the developing but immature chick retina, iodopsin immunoreactivity was found at the plasma membranes of both the IS and the terminals (pedicles) [8].
• However, chicken iodopsin activated the enzyme in frog rod outer segment membrane without irradiation, while chicken rhodopsin did not [9].
• The chicken retina has several types of cone photoreceptor cells, each of which contains a visual pigment, chicken red (iodopsin), green, blue or violet [10].
• Monoclonal antibodies (mABs) from hybridoma cells were raised and screened with a purified cone pigment, iodopsin, from the chicken retina [11].

Associations of OPN1LW with chemical compounds

• There existed an equilibrium between two forms of iodopsin with a dissociation constant of 0.8 mM chloride [12].
• In addition to the blue shift of the absorption maximum upon substituting nitrate for chloride, the C=C stretching vibrations of iodopsin and its photoproducts were upshifted 5-6 cm(-)(1) [13].
• The photobleaching process of iodopsin (a chicken red-sensitive cone visual pigment) purified in a detergent system containing CHAPS and phosphatidylcholine was investigated by means of nanosecond laser photolysis at room temperature [14].
• All these facts suggest that the chloride binding site of iodopsin does not accept a divalent anion such as SO4(2+), but does accept a monovalent anion such as Cl- or NO3-, which causes inhibition of the chromophore transfer [12].
• Sodium borohydride reduction of iodopsin [15].

Other interactions of OPN1LW

• We have purified and reconstituted both chicken rhodopsin and chicken iodopsin and shown them to be phosphorylated by bovine rhodopsin kinase [6].
• The iodopsin and AANAT mRNA rhythms re-emerged in the cultured retinas within 24 h of removal of the compounds [16].
• In this study, we compared mRNA levels of iodopsin and the chicken homolog of Clock (cClock) in the retinas of normal and rd (retinal degeneration) chickens that lack functional rod and cone phototransduction cascades [17].
• To understand the origin of this opsin shift and the mechanism of wavelength regulation in iodopsin, a series of synthetic 9-cis and 11-cis dehydro- and dihydro-retinals was used to regenerate iodopsin-based pigments [18].
• We compared the rhythmic changes in transcript levels of iodopsin, a photoreceptor-specific gene whose expression is regulated by circadian oscillators, in retinas of normal chickens and GUCY1*B (*B) chickens that carry a null mutation in GC1 [19].

Analytical, diagnostic and therapeutic context of OPN1LW

• Antibody-dependent differences in the staining intensity of the 34 kDa band containing iodopsin were observed on western blots of +/+, +/rd, and rd/rd retinal protein [1].
• Chloride effect on iodopsin studied by low-temperature visible and infrared spectroscopies [20].
• Circular dichroism of metaiodopsin II and its binding to transducin: a comparative study between meta II intermediates of iodopsin and rhodopsin [21].
• Based on the results of the cDNA sequence and northern blot experiments, the authors conclude that the gene encoding iodopsin and transcription of this gene are normal in the rd mutant [1].
• Photoreceptor cell types in the retina of various vertebrate species: immunocytochemistry with antibodies against rhodopsin and iodopsin [22].

References