The central objective of this proposal is to define the molecular genetics of red/green color vision by relating the molecular genetics of the X- linked photopigment genes to their expression in the retina and to the color vision phenotype. The red and green pigment genes are arranged in an array on the X-chromosome consisting of a single red and one or more green pigment genes. Deletion of genes or formation of hybrid genes (red-green and green-red) due to illegitimate recombination at this locus causes color vision defects. However, not all other gens of the red/green array are expressed in the retina, creating uncertainties in predicting color vision phenotype from genotype. Understanding the mechanism by which selective expression of these genes is accomplished is fundamental to defining genotype-phenotype relationships. We have delineated critical regulatory regions of the red-green gene locus and detected proteins that bind to them. A major aim of this proposal is to clone and character the transcription factors that play major roles in regulating expression of the visual pigment genes. We will map the genes encoding these factors on human and mouse chromosomes. Map positions will be correlated with known loci associated with retinal diseases. We developed a rapid method for determining gene order in males who have up to three pigment genes in their arrays and found evidence for a role of gene order in gene expression and color vision. We propose to advance their method in order to determine gene order in the majority of individuals. Knowing the sequence and gene order will allow more precise prediction of the spectral sensitivities of clones and the color vision phenotype. The ratio of red to green cones was determined indirectly by measuring relative levels of mRNA in postmortem human retinae. We propose to determine the ratio and distribution of cones in the retina directly by in situ molecular techniques. The findings will be of fundamental importance for the visual sciences. We observed a very high frequency of green-red hybrid genes among Africans. We will investigate the sequence of these hybrids and determine their position in the array. Elucidation of the molecular mechanism of expression of this locus affecting sensory perception is a model for expression of genes in other complex loci. These studies may lead to rapid and accurate blood tests for color vision defects. The novel photoreceptor-specific genes we propose to clone may be good candidates for some of the inherited retinal diseases.

National Institute of Health (NIH)
National Eye Institute (NEI)
Research Project (R01)
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Visual Sciences C Study Section (VISC)
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Dudley, Peter A
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University of Washington
Internal Medicine/Medicine
Schools of Medicine
United States
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Jordan, Gabriele; Deeb, Samir S; Bosten, Jenny M et al. (2010) The dimensionality of color vision in carriers of anomalous trichromacy. J Vis 10:12
Deeb, S S; Bisset, D; Fu, L (2010) Epigenetic control of expression of the human L- and M- pigment genes. Ophthalmic Physiol Opt 30:446-53
Liu, Yan; Fu, Li; Chen, Ding-Geng et al. (2007) Identification of novel retinal target genes of thyroid hormone in the human WERI cells by expression microarray analysis. Vision Res 47:2314-26
Deeb, S S (2005) The molecular basis of variation in human color vision. Clin Genet 67:369-77
Hayashi, Takaaki; Huang, Jing; Deeb, Samir S (2005) Expression of rinx/vsx1 during postnatal eye development in cone-bipolar, differentiating ganglion, and lens fiber cells. Jpn J Ophthalmol 49:93-105
Deeb, Samir S (2004) Molecular genetics of colour vision deficiencies. Clin Exp Optom 87:224-9
Young, Terri L; Deeb, Samir S; Ronan, Shawn M et al. (2004) X-linked high myopia associated with cone dysfunction. Arch Ophthalmol 122:897-908
Deeb, Samir S; Kohl, Susanne (2003) Genetics of color vision deficiencies. Dev Ophthalmol 37:170-87
Jagla, Wolfgang M; Jagle, Herbert; Hayashi, Takaaki et al. (2002) The molecular basis of dichromatic color vision in males with multiple red and green visual pigment genes. Hum Mol Genet 11:23-32
Deeb, S S; Diller, L C; Williams, D R et al. (2000) Interindividual and topographical variation of L:M cone ratios in monkey retinas. J Opt Soc Am A Opt Image Sci Vis 17:538-44

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