Ying S, Jansen H T, Lehman M N, Fong S L, Kao W W
Departments of Ophthalmology and Cell Biology, Neurobiology and Anatomy, University of Cincinnati, Cincinnati, OH 45267-0527, USA.
Mol Vis. 2000 Jun 24;6:101-8.
To examine the effect of loss of cone photoreceptor cells on retinal degeneration.
We previously identified a cone photoreceptor cell-specific promoter of human cone transducin a-subunit (GNAT2) gene. In this report, a minigene, Trc-Tox176, that contains the GNAT2 promoter, an attenuated diphtheria toxin A-chain gene, and an enhancer element from human interphotoreceptor retinoid-binding protein (IRBP) was used to generate coneless transgenic mice. Transgenic mice were identified by PCR and the copy number of the transgene was determined by Southern hybridization, and examined by histology.
The results of immunostaining with anti-mouse GNAT2 antibodies and reverse transcription-PCR (RT-PCR) analysis with mRNA from the retinas of transgenic mice showed that cone photoreceptor cells were ablated in one of four transgenic mouse lines. The ablation of cone cells began at postnatal day 8, at the same time as the expression of endogenous GNAT2. An age-related rod degeneration was also found in this cone-ablated mouse line, beginning at postnatal day 9, proceeding from the central retina to the peripheral retina.
Cone photoreceptor cells may play an important role in the survival of rod photoreceptor cells during mouse retina development.
研究视锥光感受器细胞缺失对视网膜变性的影响。
我们之前鉴定出了人类视锥转导蛋白α亚基（GNAT2）基因的视锥光感受器细胞特异性启动子。在本报告中，使用了一个包含GNAT2启动子、减毒白喉毒素A链基因和来自人类视网膜间视黄醇结合蛋白（IRBP）的增强子元件的小基因Trc-Tox176来生成无视锥转基因小鼠。通过PCR鉴定转基因小鼠，并通过Southern杂交确定转基因的拷贝数，然后进行组织学检查。
用抗小鼠GNAT2抗体进行免疫染色以及对转基因小鼠视网膜mRNA进行逆转录PCR（RT-PCR）分析的结果表明，在四个转基因小鼠品系中的一个品系中视锥光感受器细胞被消除。视锥细胞的消除在出生后第8天开始，与内源性GNAT2的表达同时发生。在这个视锥细胞被消除的小鼠品系中还发现了与年龄相关的视杆细胞变性，从出生后第9天开始，从视网膜中央向周边发展。
在小鼠视网膜发育过程中，视锥光感受器细胞可能在视杆光感受器细胞的存活中发挥重要作用。
