<i>Atp1b2<sup>Atp1b1</sup></i> Knock-In Mice Exhibit a Cone–Rod Dystrophy-Like Phenotype
The Na,K-ATPase is a heterodimeric ion pump consisting of various combinations of a catalytic α-subunit (α1, α2, α3, or α4, encoded by <i>ATP1A1–ATP1A4</i>) and a β-subunit (β1, β2, or β3, encoded by <i>ATP1B1–ATP1B3</i>). We have previously shown that <i>Atp1b2</i&g...
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2025-06-01
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| author | Susanne Bartsch Yevgeniya Atiskova Stefanie Schlichting Elke Becker Maike Herrmann Udo Bartsch |
| author_facet | Susanne Bartsch Yevgeniya Atiskova Stefanie Schlichting Elke Becker Maike Herrmann Udo Bartsch |
| author_sort | Susanne Bartsch |
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| description | The Na,K-ATPase is a heterodimeric ion pump consisting of various combinations of a catalytic α-subunit (α1, α2, α3, or α4, encoded by <i>ATP1A1–ATP1A4</i>) and a β-subunit (β1, β2, or β3, encoded by <i>ATP1B1–ATP1B3</i>). We have previously shown that <i>Atp1b2</i> knock-out (ko) mice exhibit rapid photoreceptor cell degeneration, whereas <i>Atp1b2<sup>Atp1b1</sup></i> knock-in (ki) mice, which express the β1-subunit instead of the β2-subunit under regulatory elements of the <i>Atp1b2</i> gene, exhibit slowly progressive retinal dystrophy. Here, we performed a detailed analysis of the retinal phenotype of the <i>Atp1b2<sup>Atp1b1</sup></i> ki mouse. We found that the number of cone photoreceptor cells in the mutant retinas was significantly reduced by postnatal day 28. The retinas of 4-month-old mice were almost devoid of cones. The early onset and rapid loss of cones was followed by a slowly progressive degeneration of rods. Other retinal cell types were unaffected. Nonradioactive <i>in situ</i> hybridization and immunohistochemistry revealed that wild-type photoreceptors expressed β3 and high levels of β2, while <i>Atp1b2<sup>Atp1b1</sup></i> ki photoreceptor cells expressed β3 and low levels of transgenic β1. Additionally, levels of retinoschisin, a secreted retina-specific protein that interacts directly with the β2-subunit, were greatly reduced in mutant retinas. The results demonstrate that the β1-subunit can functionally compensate, at least in part, for the absence of the β2-subunit. The results also show that cones are more susceptible to Na,K-ATPase dysfunction than rods. Taken together, the present study identifies the <i>Atp1b2<sup>Atp1b1</sup></i> ki mutant as a novel animal model of an early-onset and rapidly progressive cone–rod dystrophy. |
| format | Article |
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| institution | Kabale University |
| issn | 2073-4409 |
| language | English |
| publishDate | 2025-06-01 |
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| spelling | doaj-art-4f7487c7d17644da91e01f3619f141702025-08-20T03:27:28ZengMDPI AGCells2073-44092025-06-01141287810.3390/cells14120878<i>Atp1b2<sup>Atp1b1</sup></i> Knock-In Mice Exhibit a Cone–Rod Dystrophy-Like PhenotypeSusanne Bartsch0Yevgeniya Atiskova1Stefanie Schlichting2Elke Becker3Maike Herrmann4Udo Bartsch5Department of Ophthalmology, Experimental Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, GermanyDepartment of Ophthalmology, Experimental Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, GermanyDepartment of Ophthalmology, Experimental Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, GermanyDepartment of Ophthalmology, Experimental Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, GermanyDepartment of Ophthalmology, Experimental Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, GermanyDepartment of Ophthalmology, Experimental Ophthalmology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, GermanyThe Na,K-ATPase is a heterodimeric ion pump consisting of various combinations of a catalytic α-subunit (α1, α2, α3, or α4, encoded by <i>ATP1A1–ATP1A4</i>) and a β-subunit (β1, β2, or β3, encoded by <i>ATP1B1–ATP1B3</i>). We have previously shown that <i>Atp1b2</i> knock-out (ko) mice exhibit rapid photoreceptor cell degeneration, whereas <i>Atp1b2<sup>Atp1b1</sup></i> knock-in (ki) mice, which express the β1-subunit instead of the β2-subunit under regulatory elements of the <i>Atp1b2</i> gene, exhibit slowly progressive retinal dystrophy. Here, we performed a detailed analysis of the retinal phenotype of the <i>Atp1b2<sup>Atp1b1</sup></i> ki mouse. We found that the number of cone photoreceptor cells in the mutant retinas was significantly reduced by postnatal day 28. The retinas of 4-month-old mice were almost devoid of cones. The early onset and rapid loss of cones was followed by a slowly progressive degeneration of rods. Other retinal cell types were unaffected. Nonradioactive <i>in situ</i> hybridization and immunohistochemistry revealed that wild-type photoreceptors expressed β3 and high levels of β2, while <i>Atp1b2<sup>Atp1b1</sup></i> ki photoreceptor cells expressed β3 and low levels of transgenic β1. Additionally, levels of retinoschisin, a secreted retina-specific protein that interacts directly with the β2-subunit, were greatly reduced in mutant retinas. The results demonstrate that the β1-subunit can functionally compensate, at least in part, for the absence of the β2-subunit. The results also show that cones are more susceptible to Na,K-ATPase dysfunction than rods. Taken together, the present study identifies the <i>Atp1b2<sup>Atp1b1</sup></i> ki mutant as a novel animal model of an early-onset and rapidly progressive cone–rod dystrophy.https://www.mdpi.com/2073-4409/14/12/878ATP1A3ATP1B2bipolar cellsconescone–rod dystrophydegeneration |
| spellingShingle | Susanne Bartsch Yevgeniya Atiskova Stefanie Schlichting Elke Becker Maike Herrmann Udo Bartsch <i>Atp1b2<sup>Atp1b1</sup></i> Knock-In Mice Exhibit a Cone–Rod Dystrophy-Like Phenotype Cells ATP1A3 ATP1B2 bipolar cells cones cone–rod dystrophy degeneration |
| title | <i>Atp1b2<sup>Atp1b1</sup></i> Knock-In Mice Exhibit a Cone–Rod Dystrophy-Like Phenotype |
| title_full | <i>Atp1b2<sup>Atp1b1</sup></i> Knock-In Mice Exhibit a Cone–Rod Dystrophy-Like Phenotype |
| title_fullStr | <i>Atp1b2<sup>Atp1b1</sup></i> Knock-In Mice Exhibit a Cone–Rod Dystrophy-Like Phenotype |
| title_full_unstemmed | <i>Atp1b2<sup>Atp1b1</sup></i> Knock-In Mice Exhibit a Cone–Rod Dystrophy-Like Phenotype |
| title_short | <i>Atp1b2<sup>Atp1b1</sup></i> Knock-In Mice Exhibit a Cone–Rod Dystrophy-Like Phenotype |
| title_sort | i atp1b2 sup atp1b1 sup i knock in mice exhibit a cone rod dystrophy like phenotype |
| topic | ATP1A3 ATP1B2 bipolar cells cones cone–rod dystrophy degeneration |
| url | https://www.mdpi.com/2073-4409/14/12/878 |
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