Ophthalmology Commons^™

Genetic Modification Of Inherited Retinopathy In Mice, Yang Kong

Electronic Theses and Dissertations

The retina, as a critical component of the sensory system, consists of multiple cell types, of which, photoreceptors play a key role in receiving, integrating and transmitting light signals. The biofunctions of photoreceptors rely on their proper growth and development, which is predominantly governed by a cluster of molecules that comprise the transcriptional regulation for photoreceptor development. Any disruption of these molecules potentially incurs retinal pathologies.

It is known that deficiencies of nuclear receptor subfamily 2 group E member 3 (NR2E3) or neural retina leucine-zipper (NRL), two molecules in regulating photoreceptor cell development, cause photoreceptor dysplasia. In a sensitized chemical …

Identification Of Genetic Variation And Haplotype Structure Of The Canine Abca4 Gene For Retinal Disease Association Studies, Barbara Zangerl, Sarah J. Lindauer, Gregory M. Acland, Gustavo D. Aguirre

Gustavo D. Aguirre, VMD, PhD

Over 200 mutations in the retina specific member of the ATP-binding cassette transporter superfamily (ABCA4) have been associated with a diverse group of human retinal diseases. The disease mechanisms, and genotype–phenotype associations, nonetheless, remain elusive in many cases. As orthologous genes are commonly mutated in canine models of human blinding disorders, canine ABCA4 appears to be an ideal candidate gene to identify and study sequence changes in dogs affected by various forms of inherited retinal degeneration. However, the size of the gene and lack of haplotype assignment significantly limit targeted association and/or linkage approaches. This study assessed the naturally observed …

Modeling The Structural Consequences Of Best1 Missense Mutations, Karina E. Guziewicz, Gustavo D. Aguirre, Barbara Zangerl

Gustavo D. Aguirre, VMD, PhD

Mutations in the bestrophin-1 gene (BEST1) are an important cause of inherited retinal disorders. Hitherto, over 100 unique allelic variants have been linked to the human BEST1 (hBEST1), and associated with disease phenotypes, broadly termed as bestrophinopathies. A spontaneous animal model recapitulating BEST1-related phenotypes, canine multifocal retinopathy (cmr), is caused by mutations in the canine gene ortholog (cBEST1). We have recently characterized molecular consequences of cmr, demonstrating defective protein trafficking as a result of G161D (cmr2) mutation. To further investigate the pathological effects of BEST1 missense mutations, canine and human peptide fragments derived from the protein sequence have been studied …

Development And Validation Of A Canine-Specific Profiling Array To Examine Expression Of Pro-Apoptotic And Pro-Survival Genes In Retinal Degenerative Diseases, Sem Genini, William Beltran, Gustavo D. Aguirre

Gustavo D. Aguirre, VMD, PhD

We developed an expression profiling array to examine pro-apoptotic and pro-survival genes in dog retinal degeneration models. Gene-specific canine TaqMan assays were developed and included in a custom real-time quantitative reverse transcription-PCR (qRT-PCR) array. Of the 96 selected genes, 93 belonged to known relevant pro-apoptotic and pro-survival pathways, and/or were positive controls expressed in retina, while three were housekeeping genes. Ingenuity Pathway Analysis (IPA) showed that the selected genes belonged to expected biological functions (cell death, cell-mediated immune response, cellular development, function, and maintenance) and pathways (death receptor signaling, apoptosis, TNFR1 signaling, and induction of apoptosis by HIV1). Validation of …

Linkage Disequilibrium Mapping In Domestic Dog Breeds Narrows The Progressive Rod-Cone Degeneration Interval And Identifies Ancestral Disease-Transmitting Chromosome, Orly Goldstein, Barbara Zangerl, Sue Pearce-Kelling, Duska J. Sidjanin, James W. Kijas, Jeanette Felix, Gregory M. Acland, Gustavo D. Aguirre

Gustavo D. Aguirre, VMD, PhD

Canine progressive rod–cone degeneration (prcd) is a retinal disease previously mapped to a broad, gene-rich centromeric region of canine chromosome 9. As allelic disorders are present in multiple breeds, we used linkage disequilibrium (LD) to narrow the ∼6.4-Mb interval candidate region. Multiple dog breeds, each representing genetically isolated populations, were typed for SNPs and other polymorphisms identified from BACs. The candidate region was initially localized to a 1.5-Mb zero recombination interval between growth factor receptor-bound protein 2 (GRB2) and SEC14-like 1 (SEC14L). A fine-scale haplotype of the region was developed, which reduced the LD interval to 106 kb and identified …

Accumulation Of Rhodopsin In Late Endosomes Triggers Photoreceptor Cell Degeneration, Yashodhan Chinchore, Amitavo Mitra, Patrick J. Dolph, Norbert Perrimon

Dartmouth Scholarship

Progressive retinal degeneration is the underlying feature of many human retinal dystrophies. Previous work using Drosophila as a model system and analysis of specific mutations in human rhodopsin have uncovered a connection between rhodopsin endocytosis and retinal degeneration. In these mutants, rhodopsin and its regulatory protein arrestin form stable complexes, and endocytosis of these complexes causes photoreceptor cell death. In this study we show that the internalized rhodopsin is not degraded in the lysosome but instead accumulates in the late endosomes. Using mutants that are defective in late endosome to lysosome trafficking, we were able to show that rhodopsin accumulates …