Deletion of POMT2 in Zebrafish Causes Degeneration of Photoreceptors
Mutations in the extracellular matrix protein eyes shut homolog (EYS) are a common cause of retinitis pigmentosa, a blinding disease characterized by photoreceptor degeneration. EYS binds to matriglycan, a carbohydrate modification on O-mannosyl glycan substitutions of the cell-surface glycoprotein...
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MDPI AG
2022-11-01
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| Series: | International Journal of Molecular Sciences |
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| author | Yu Liu Jaclyn M. Rittershaus Miao Yu Rachel Sager Huaiyu Hu |
| author_facet | Yu Liu Jaclyn M. Rittershaus Miao Yu Rachel Sager Huaiyu Hu |
| author_sort | Yu Liu |
| collection | DOAJ |
| description | Mutations in the extracellular matrix protein eyes shut homolog (EYS) are a common cause of retinitis pigmentosa, a blinding disease characterized by photoreceptor degeneration. EYS binds to matriglycan, a carbohydrate modification on O-mannosyl glycan substitutions of the cell-surface glycoprotein α-dystroglycan. Patients with mutations in enzymes required for the biosynthesis of matriglycan exhibit syndromic retinal atrophy, along with brain malformations and congenital muscular dystrophy. Protein O-mannosyltransferase 2 (POMT2) is an enzyme required for the synthesis of O-mannosyl glycans. To evaluate the roles of O-mannosyl glycans in photoreceptor health, we generated <i>protein O-mannosyltransferase 2 (pomt2)</i> mutant zebrafish by CRISPR. <i>pomt2</i> mutation resulted in a loss of matriglycan and abolished binding of EYS protein to α-dystroglycan. Mutant zebrafish presented with hydrocephalus and hypoplasia of the cerebellum, as well as muscular dystrophy. EYS protein was enriched near photoreceptor connecting cilia in the wild-type, but its presence and proper localization was significantly reduced in mutant animals. The mutant retina exhibited mis-localization of opsins and increased apoptosis in both rod and cone photoreceptors. Immunofluorescence intensity of G protein subunit alpha transducin 2 (GNAT2) antibody (a general cone marker) and 1D4 antibody (a long double cone marker) in mutant retinas did not differ from wild-type retinas at 1-month post fertilization, but was reduced at 6 months post fertilization, indicating significant cone degeneration. These data suggest that POMT2-mediated O-mannosyl glycosylation is required for EYS protein localization to the connecting cilium region and photoreceptor survival. |
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| language | English |
| last_indexed | 2024-03-09T17:46:16Z |
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| series | International Journal of Molecular Sciences |
| spelling | doaj.art-35a88056de3349fd9e013f6615c2efa62023-11-24T11:08:18ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672022-11-0123231480910.3390/ijms232314809Deletion of POMT2 in Zebrafish Causes Degeneration of PhotoreceptorsYu Liu0Jaclyn M. Rittershaus1Miao Yu2Rachel Sager3Huaiyu Hu4Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY 13210, USACenter for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY 13210, USACenter for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY 13210, USACenter for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY 13210, USACenter for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY 13210, USAMutations in the extracellular matrix protein eyes shut homolog (EYS) are a common cause of retinitis pigmentosa, a blinding disease characterized by photoreceptor degeneration. EYS binds to matriglycan, a carbohydrate modification on O-mannosyl glycan substitutions of the cell-surface glycoprotein α-dystroglycan. Patients with mutations in enzymes required for the biosynthesis of matriglycan exhibit syndromic retinal atrophy, along with brain malformations and congenital muscular dystrophy. Protein O-mannosyltransferase 2 (POMT2) is an enzyme required for the synthesis of O-mannosyl glycans. To evaluate the roles of O-mannosyl glycans in photoreceptor health, we generated <i>protein O-mannosyltransferase 2 (pomt2)</i> mutant zebrafish by CRISPR. <i>pomt2</i> mutation resulted in a loss of matriglycan and abolished binding of EYS protein to α-dystroglycan. Mutant zebrafish presented with hydrocephalus and hypoplasia of the cerebellum, as well as muscular dystrophy. EYS protein was enriched near photoreceptor connecting cilia in the wild-type, but its presence and proper localization was significantly reduced in mutant animals. The mutant retina exhibited mis-localization of opsins and increased apoptosis in both rod and cone photoreceptors. Immunofluorescence intensity of G protein subunit alpha transducin 2 (GNAT2) antibody (a general cone marker) and 1D4 antibody (a long double cone marker) in mutant retinas did not differ from wild-type retinas at 1-month post fertilization, but was reduced at 6 months post fertilization, indicating significant cone degeneration. These data suggest that POMT2-mediated O-mannosyl glycosylation is required for EYS protein localization to the connecting cilium region and photoreceptor survival.https://www.mdpi.com/1422-0067/23/23/14809retinaretinitis pigmentosaphotoreceptor degenerationinherited retinal degenerationzebrafishcongenital muscular dystrophy |
| spellingShingle | Yu Liu Jaclyn M. Rittershaus Miao Yu Rachel Sager Huaiyu Hu Deletion of POMT2 in Zebrafish Causes Degeneration of Photoreceptors International Journal of Molecular Sciences retina retinitis pigmentosa photoreceptor degeneration inherited retinal degeneration zebrafish congenital muscular dystrophy |
| title | Deletion of POMT2 in Zebrafish Causes Degeneration of Photoreceptors |
| title_full | Deletion of POMT2 in Zebrafish Causes Degeneration of Photoreceptors |
| title_fullStr | Deletion of POMT2 in Zebrafish Causes Degeneration of Photoreceptors |
| title_full_unstemmed | Deletion of POMT2 in Zebrafish Causes Degeneration of Photoreceptors |
| title_short | Deletion of POMT2 in Zebrafish Causes Degeneration of Photoreceptors |
| title_sort | deletion of pomt2 in zebrafish causes degeneration of photoreceptors |
| topic | retina retinitis pigmentosa photoreceptor degeneration inherited retinal degeneration zebrafish congenital muscular dystrophy |
| url | https://www.mdpi.com/1422-0067/23/23/14809 |
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