Purpose: This investigation examines the genetic sources of marked variation in cone photoreceptor number among inbred lines of mice, identifying candidate genes that may control the proliferation, differentiation, or survival of this neuronal population.
Methods: Cone photoreceptor populations were counted in C57BL/6J (B6/J) and A/J strains, and 26 recombinant inbred (RI) strains derived from them. Eyes from RI strains were also collected for microarray analysis. Quantitative trait locus (QTL) analysis was carried out by simple and composite interval mapping and validated using a consomic line. Candidate genes were evaluated based on genetic variance between the parental strains and analysis of gene expression. Expression data, deposited in GeneNetwork (www.GeneNetwork.org), were used to generate a coexpression network of established cone photoreceptor genes as a reference standard.
Results: B6/J has 70% more cone photoreceptors than A/J. A significant QTL was mapped to chromosome 10 (Chr 10) and confirmed using B6.A<10> mice. Of 19 positional candidate genes, one-the myeloblastosis oncogene (Myb)-stood out. Myb has a potentially damaging missense mutation, high retinal expression, and a known role in cell proliferation. The ectonucleotide pyrophosphatase/phosphodiesterase 1 gene (Enpp1) was a second strong candidate, with an expression pattern that covaried with cone photoreceptors and that was differentially expressed between the parental strains. Enpp1 and several other candidate genes covaried with multiple genes within the cone photoreceptor gene network.
Conclusions: The mouse retina shows marked variation in cone photoreceptor number, some of which must be controlled by polymorphisms in a gene or genes on Chr 10.
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http://dx.doi.org/10.1167/iovs.10-6693 | DOI Listing |
Cells
January 2025
Department of Pharmacology, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106, USA.
Retinitis pigmentosa (RP) is a hereditary disease characterized by progressive vision loss ultimately leading to blindness. This condition is initiated by mutations in genes expressed in retinal cells, resulting in the degeneration of rod photoreceptors, which is subsequently followed by the loss of cone photoreceptors. Mutations in various genes expressed in the retina are associated with RP.
View Article and Find Full Text PDFCell Syst
December 2024
The Edison Family Center for Genome Sciences & Systems Biology, Saint Louis, MO 63110, USA; Department of Genetics, Saint Louis, MO 63110, USA. Electronic address:
Deep learning is a promising strategy for modeling cis-regulatory elements. However, models trained on genomic sequences often fail to explain why the same transcription factor can activate or repress transcription in different contexts. To address this limitation, we developed an active learning approach to train models that distinguish between enhancers and silencers composed of binding sites for the photoreceptor transcription factor cone-rod homeobox (CRX).
View Article and Find Full Text PDFEye (Lond)
January 2025
Division of Experimental Retinal Therapies, Department of Clinical Sciences, University of Pennsylvania, School of Veterinary Medicine, Philadelphia, PA, 19104, USA.
In this review, we summarize the findings of several pre-clinical studies in the canine BEST1 disease model. To this end, client-owned and purpose bred dogs that were compound heterozygotes or homozygotes, respectively, for two or one of 3 different mutations in BEST1 were evaluated by ophthalmic examination, cSLO/sdOCT imaging, and retinal immunohistochemistry to characterize the clinical and microanatomic features of the disease. Subsequently AAV-mediated gene therapy was done to transfer the BEST1 transgene to the RPE under control of a hVMD2 promoter.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA 52242.
Cone cGMP-phosphodiesterase (PDE6) is the key effector enzyme for daylight vision, and its properties are critical for shaping distinct physiology of cone photoreceptors. We determined the structures of human cone PDE6C in various liganded states by single-particle cryo-EM that reveal essential functional dynamics and adaptations of the enzyme. Our analysis exposed the dynamic nature of PDE6C association with its regulatory γ-subunit (Pγ) which allows openings of the catalytic pocket in the absence of phototransduction signaling, thereby controlling photoreceptor noise and sensitivity.
View Article and Find Full Text PDFNeurobiol Dis
December 2024
Department of Physiology & Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA. Electronic address:
Huntington's disease (HD) is caused by the expansion of a CAG repeat, encoding a string of glutamines (polyQ) in the first exon of the huntingtin gene (HTTex1). This mutant huntingtin protein (mHTT) with extended polyQ forms aggregates in cortical and striatal neurons, causing cell damage and death. The retina is part of the central nervous system (CNS), and visual deficits and structural abnormalities in the retina of HD patients have been observed.
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