Knockout of Nr2e3 prevents rod photoreceptor differentiation and leads to selective L-/M-cone photoreceptor degeneration in zebrafish
Knockout of Nr2e3 prevents rod photoreceptor differentiation and leads to selective L-/M-cone photoreceptor degeneration in zebrafish
复制标题
Nr2e3 的敲除会阻止斑马鱼视杆细胞分化并导致选择性 L-/M-视锥细胞变性。
DOI：
10.1016/j.bbadis.2019.01.022
复制
发表时间：
2019-06-01
影响因子：
6.2
通讯作者：
Liu, Mugen
中科院分区：
文献类型：
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作者：
Xie, Shanglun;Han, Shanshan;Liu, Mugen
感光细胞特异性核受体基因Nr 2 e3的突变增加了人类和小鼠视网膜中S-视锥感光细胞的数量，并导致涉及感光细胞和非感光细胞的视网膜变性。这些复杂表型的机制仍不清楚。为了了解Nr 2 e3在光感受器细胞命运决定和分化中的确切作用，我们使用CRISPR技术产生了Nr 2 e3敲除斑马鱼系。在这些Nr 2 e3-null动物中，杆前体经历终末有丝分裂，但不能分化为杆。视杆特异性基因不表达，外节（OS）未能形成。视锥细胞的形成和分化是正常的。具体而言，UV-视锥或S-视锥光感受器的数量没有增加。视网膜分层结构得以维持。正常发育后，L-/M-视锥细胞选择性退化，OS从1个月大开始逐渐缩短。锥光转导蛋白的量是伴随减少，而UV-和S-锥有正常的OS长度，即使在10个月大。体外研究显示，Nr 2 e3与Crx和Nrl协同增强视紫红质基因表达。Nr 2 e3不影响视锥细胞视蛋白的表达。我们的研究结果扩展了Nr 2 e3的作用的知识，并对人类和小鼠视网膜中观察到的表型的解释有特定的影响。此外，我们的模型可能为寻找增强型S-视锥综合征（ESCS）和其他视网膜退行性疾病的治疗方法提供新的机会。
Mutations in the photoreceptor cell-specific nuclear receptor gene Nr2e3 increased the number of S-cone photoreceptors in human and murine retinas and led to retinal degeneration that involved photoreceptor and non photoreceptor cells. The mechanisms underlying these complex phenotypes remain unclear. In the hope of understanding the precise role of Nr2e3 in photoreceptor cell fate determination and differentiation, we generated a line of Nr2e3 knockout zebrafish using CRISPR technology. In these Nr2e3-null animals, rod precursors undergo terminal mitoses but fail to differentiate as rods. Rod-specific genes are not expressed and the outer segment (OS) fails to form. Formation and differentiation of cone photoreceptors is normal. Specifically, there is no increase in the number of UV-cone or S-cone photoreceptors. Laminated retinal structure is maintained. After normal development, L-/M-cones selectively degenerate, with progressive shortening of OS that starts at age 1 month. The amount of cone phototransduction proteins is concomitantly reduced, whereas UV- and S-cones have normal OS lengths even at age 10 months. In vitro studies show Nr2e3 synergizes with Crx and Nrl to enhance rhodopsin gene expression. Nr2e3 does not affect cone opsin expression. Our results extend the knowledge of Nr2e3's roles and have specific implications for the interpretation of the phenotypes observed in human and murine retinas. Furthermore, our model may offer new opportunities in finding treatments for enhanced S-cone syndrome (ESCS) and other retinal degenerative diseases.