University of Zurich, Department of Molecular Life Sciences, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
Invest Ophthalmol Vis Sci. 2024 Oct 1;65(12):44. doi: 10.1167/iovs.65.12.44.
To define the location of mglur6 paralogs in the outer zebrafish retina and delineate their contribution to retina light responses across the visual spectrum.
In situ hybridization and immunolocalization with custom-made antibodies were used to localize mglur6 transcripts, proteins, and additional components of the mGluR6 signaling complex. Gene editing was used to generate knockout mutants that were analyzed with white light and spectral electroretinography.
Both mglur6 paralogs colocalized with known downstream pathway genes, such as trpm1a, nyctalopin, and gnaoβ. All rod photoreceptors contacted mGluR6-positive cells, while cone connectivity presented a more complex situation with no red cones and only a few UV and blue-sensitive cones connecting to mGluR6a-positive bipolar cells. All cone subtypes contacted mGluR6b-positive cells with markedly fewer red-sensitive cones. Retinas of knockout animals displayed no morphologic alterations. While ERG responses were unaffected in mglur6a knockout animals, mglur6b mutants displayed decreased responses over all spectral wavelengths.
We demonstrated that mGlurR6 signalplex components are similar in the zebrafish and the mammalian retina. Despite mglur6b knockout animals having significantly impaired ERG b-wave responses, a residual b-wave persists, even in double knockouts, suggesting additional pathway components yet to be identified.
确定外节斑马鱼视网膜中 mglur6 旁系同源物的位置，并阐明它们对视觉光谱范围内视网膜光反应的贡献。
使用原位杂交和定制抗体的免疫定位来定位 mglur6 转录本、蛋白质和 mGluR6 信号复合物的其他成分。基因编辑用于生成缺失突变体，并用白光和光谱视网膜电图进行分析。
两个 mglur6 旁系同源物都与已知的下游途径基因如 trpm1a、nyctalopin 和 gnaoβ共定位。所有视杆细胞都与 mGluR6 阳性细胞接触，而锥体连接则呈现出更为复杂的情况，没有红色锥体，只有少数 UV 和蓝色敏感锥体与 mGluR6a 阳性双极细胞接触。所有锥体亚型都与 mGluR6b 阳性细胞接触，但红色敏感锥体明显较少。缺失动物的视网膜没有形态改变。虽然 mglur6a 缺失动物的 ERG 反应不受影响，但 mglur6b 突变体在所有光谱波长下的反应都减少。
我们证明了 mGlurR6 信号复合物在斑马鱼和哺乳动物视网膜中的成分相似。尽管 mglur6b 缺失动物的 ERG b 波反应明显受损，但即使在双缺失动物中，仍存在残留的 b 波，这表明还有其他尚未确定的途径成分。
