Molecular mechanism of dominant retinal degeneration in mice resulted from a point mutation in the Rom1 gene.

小鼠显性视网膜变性的分子机制是由 Rom1 基因点突变引起的。

• 批准号: 18591906
• 负责人: SATO Hajime
• 金额: $ 2.5万
• 依托单位: TOHOKU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2006
• 资助国家: 日本
• 起止时间: 2006 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18591906/
• 关键词: retinal degeneration; Rom1 gene; Peripherin; rds gene; tetramer; 網膜色素変性; 遺伝子異常; モデル重物; モデル動物

The mutation of retinal degeneration mouse, which is designated as Rom1^<Rgsc1156>, was putative missense mutation that caused Trp to Arg substitution at position 182 of the translated protein. The codon 182 is located in the intradiscal loop of Rom1, and the intradiscal loop has been shown to play an important role in the formation of tetramers which is composed of Rom1 and/or Peropherin/rds. We performed immunohistochemistry and Western blot using the samples at 3 weeks of age, when there is little alteration of the thickness of outer nuclear layer and the length of inner and outer segments of photoreceptors. The immunohistochemical analysis revealed that the immunoreactivity for Rom1 was decreased in heterozygotes compared to that of wild-type mice. In homozygotes, the immunoreactivity was markedly reduced. In addition, the immunoreactivity for Peripherin/Rds was also decreased in heterozygotes and homozygotes.Semi-quantitative analysis for Western blots using densitometry demonstra … More ted that the immunoreactivity for Rom1 in the Rom1^<Rgsc1156> heterozygotes and homozygotes were 51.6% and 2.8% of that in wild-type mice. On the other hand, it showed that the immunoreactivity for Peripherin/rds in the Rom1^<Rgsc1156> heterozygotes and homozygotes were 59.3% and 17.4% of that in wild-type mice. These results are compatible with the results by Kedzierski that retinal degeneration could happen if the combined abundance of Rom1 and Peripherin/rds was decreased to about 60% of that in wild-type mice.The degree of retinal degeneration in Rom1^<Rgsc1156> hetrozygotes is similar to that in rds/+mice which resulted from Peripherin/rds haploinsufficiency, suggesting that the decreased levels of wild-type Rom1 and Peripherin/rds induced by mutant Rom1 caused the retinal degeneration in Rom1^<Rgsc1156> mice. The results of immunohistochemistry implied that the mutant Rom1-Peripherin/rds heterotetramers and the mutant Rom1 homotetramers degraded immediately after the subunit assembly because there was little immunoreactivity of both Rom1 and Peripherin/rds in the inner segment of the Rom1^<Rgsc1156> mutants and because there was decreased immunoreactivity of both proteins in the outer segment in genotype-dependent manner. In vitro analysis for the formation and stability of the tetramers containing mutant Rom1 will be needed. Less

视网膜变性小鼠的突变体Rom 1 ^<Rgsc1156>为错义突变，该突变导致翻译蛋白的182位Trp被Arg取代。第182位密码子位于Rom 1的椎间盘内环，并且椎间盘内环已被证明在由Rom 1和/或Peropherin/rds组成的四聚体的形成中起重要作用。我们用免疫组织化学和Western印迹法对3周龄时的样本进行了检测，此时外核层厚度和光感受器内外段长度变化不大。免疫组化分析显示，与野生型小鼠相比，Rom 1的免疫反应性在杂合子中降低。在纯合子中，免疫反应性明显降低。此外，在杂合子和纯合子中，Peripherin/Rds的免疫反应性也降低。 ...更多信息 结果表明，Rom 1 ^杂合子和纯合子小鼠的Rom 1免疫反应性<Rgsc1156>分别为野生型小鼠的51.6%和2.8%。另一方面，在Rom 1 ^杂合子和纯合子小鼠中，Peripherin/rds的免疫反应性<Rgsc1156>分别为野生型小鼠的59.3%和17.4%。这些结果与Kedzierski的结果一致，即如果Rom 1和Peripherin/rds的组合丰度降低到野生型小鼠的约60%，则可能发生视网膜变性。Rom 1 ^杂合子中的视网膜变性程度与由Peripherin/rds单倍不足导致的rds/+小鼠中的视网膜变性程度相似<Rgsc1156>，提示由突变体Rom 1诱导的野生型Rom 1和外周蛋白/rds水平的降低导致Rom 1/rds小鼠的视网膜变性<Rgsc1156>。免疫组化结果表明，突变体Rom 1-Peripherin/rds异四聚体和突变体Rom 1同源四聚体在亚基组装后立即降解，这是因为在Rom 1 ^突变体的内节中Rom 1和Peripherin/rds的免疫反应性都很低<Rgsc1156>，而在外节中这两种蛋白的免疫反应性都以基因型依赖的方式降低。需要对含有突变体Rom 1的四聚体的形成和稳定性进行体外分析。少