High impact information on Opn1mw

• Here, we show that S opsin transcription is higher than that of M opsin, which supports ultraviolet (UV) sensitivity greater than midwavelength sensitivity [1].
• A highly conserved 100-base pair (bp) sequence which is homologous to the red and green opsin locus control region is located 1.5-2 kilobases upstream of the rhodopsin gene (depending on the species) [2].
• However, little is known of the factors that directly activate these opsin genes and thereby contribute to the S or M opsin identity of the cone [3].
• Using an in vitro GTPgammaS binding assay, we also found that the ability of recombinant M opsin to activate G(t) was greatly reduced by phosphorylation [4].
• Therefore, phosphorylation may participate directly in the termination of phototransduction in cones by decreasing the activity of M opsin [4].

Biological context of Opn1mw

• Our results show that UV-opsin suppression successively ceases in presence of the M-opsin activating background light, which implies that cone light adaptation is controlled at the opsin stage, before activation of transducin [5].
• M opsin phosphorylation in intact mammalian retinas [4].
• Our results imply that in the Syrian hamster low levels of S opsin colocalize with M opsin in a common cone phenotype [6].
• To elucidate the molecular mechanisms of red-green color vision in mammals, we have cloned and sequenced the red and green opsin cDNAs of cat (Felis catus), horse (Equus caballus), gray squirrel (Sciurus carolinensis), white-tailed deer (Odocoileus virginianus), and guinea pig (Cavia porcellus) [7].
• The regularity of the cone array began to rise on P7, in parallel with the onset of mouse green opsin gene expression and the development of cone pedicles [8].

Anatomical context of Opn1mw

• Double staining with anti-Cre antibody and anti-M- or anti-S-opsin antibody revealed specificity of Cre expression in M-opsin- and/or S-opsin-positive photoreceptors [9].
• A mouse-like retinal cone phenotype in the Syrian hamster: S opsin coexpressed with M opsin in a common cone photoreceptor [6].

Regulatory relationships of Opn1mw

• Binding of endogenous TH to TRbeta2 is required to inhibit S-opsin and to activate M-opsin [10].

Other interactions of Opn1mw

• S-cones were less tolerant to bleached S-opsin than M-cones to bleached M-opsin, but still far more tolerant than mouse rods to bleached rhodopsin, which exhibit persistent suppression of nearly 50% of their circulating current following a 20% bleach [11].

References