Allelic inactivation regulates olfactory receptor gene expression.

https://www.cell.com/cell/pdf/S0092-8674(00)80439-0.pdf

Crx, a novel otx-like homeobox gene, shows photoreceptor-specific expression and regulates photoreceptor differentiation.

The G protein coupled receptors (GPC-Rs) comprise a large superfamily of genes encoding numerous receptors which all show common structural features, e.g., seven putative membrane spanning domains. Their biological functions are extremely diverse, ranging from vision and olfaction to neuronal and endocrine signaling. The GPC-Rs couple via multiple G proteins to a growing number of recognized second messenger pathway, e.g., cAMP and phosphatidyl inositol turnover. This review summarizes our current knowledge of the molecular mechanisms by which the GPC-Rs activate second messenger systems, and it addresses their regulation and structure.

Structure and Function of G Protein Coupled Receptors

The Role of Inflammation in the Pathogenesis of Age-related Macular Degeneration

Design Principles of Insect and Vertebrate Visual Systems

Blue cone monochromacy is a rare X-linked disorder of color vision characterized by the absence of both red and green cone sensitivities. In 12 of 12 families carrying this trait, alterations are observed in the red and green visual pigment gene cluster. The alterations fall into two classes. One class arose from the wild type by a two-step pathway consisting of unequal homologous recombination and point mutation. The second class arose by nonhomologous deletion of genomic DNA adjacent to the red and green pigment gene cluster. These deletions define a 579-base pair region that is located 4 kilobases upstream of the red pigment gene and 43 kilobases upstream of the nearest green pigment gene; this 579-base pair region is essential for the activity of both pigment genes.

https://science.sciencemag.org/content/sci/245/4920/831.full.pdf

Molecular Genetics of Human Blue Cone Monochromacy

Visual Evoked Potentials (VEPs) were first recorded under free viewing conditions using a B/W TV stimulator and then collected with a Maxwellian-view optical system. A blue (440 nm) reversing checkerboard pattern of 6 deg (40′ checks) was presented on a steady, yellow (575 nm), 15 deg adapting background of various luminance levels ranging over 6.5 log units. The luminance level used to evoke VEPs was set 1 log unit above the psychophysical increment threshold level. The background levels spanned both scotopic and photopic levels

VEP Measures in a Blue Cone Monochromat

Spectral sensitivity curves on a white background and F-M 100-hue test results were collected from each eye of an individual with cone-rod dystrophy. Comparing the findings for each eye revealed a striking difference between the color vision of the two eyes. For the eye with the ‘best’ acuity (0.66), results from the F-M 100 -hue test were essentially normal and the spectral sensitivity curve, while showing decreased sensitivity across the chromatic spectrum, still demonstrated the color-opponent dip found in normals. On the other hand the eye with the ‘worst’ acuity (0.4) displayed an abnormally high error score (412) with a scotopic axis on the F-M 100-hue test and the spectral sensitivity curve from this eye lacked the color-opponent ‘dip’ found in normal trichromats.

Roger L. Klingaman

Papers

Molecular Genetics of Human Blue Cone Monochromacy

VEP Measures in a Blue Cone Monochromat

Loss of Color Opponency and Concomitant Changes in FM-100 Hue Test in a Case of Cone-Rod Dystrophy