Hafezi F, Abegg M, Grimm C, Wenzel A, Munz K, Stürmer J, Farber D B, Remé C E
Department of Ophthalmology, University Hospital, Zurich, Switzerland.
Invest Ophthalmol Vis Sci. 1998 Nov;39(12):2239-44.
Apoptosis is the final common death pathway of photoreceptors in light-induced retinal degeneration and in several animal models for retinal dystrophy. To date, little is known about gene regulation of apoptosis in the retina. The expression of the immediate early gene c-fos is upregulated concomitant with apoptosis in light-induced photoreceptor degeneration and in the rd mouse, an animal model for inherited retinal degeneration. In a recent study it was shown that c-Fos is essential for light-induced apoptosis of photoreceptors in vivo. To determine whether c-Fos is also involved in the apoptotic pathway of inherited retinal degeneration, rd/rd, c-fos -/- double-mutant mice have been generated.
Double-mutant mice (rd/rd, c-fos -/-) were crossbred from c-fos+/- mice and rd/rd mice. Their genotype was determined by polymerase chain reaction analysis of genomic DNA. Wild-type control mice and homozygous rd mice were killed at 2-day intervals from postnatal day (P)9 through P21. Double-mutant mice were killed at postnatal days P9, P11, P13, P15, and P21. To determine levels of apoptosis in the retina, eyes were enucleated and processed for light microscopy and in situ nick-end labeling. Total retinal DNA was extracted from isolated retinas for DNA fragmentation analysis.
Morphologic, histochemical, and biochemical analyses showed that the time course of apoptosis and the outcome of photoreceptor degeneration in rd/rd, c-fos-/- double-mutant mice was indistinguishable from that in rd mice carrying functional c-fos.
These data suggest that in contrast to its role in light-induced photoreceptor degeneration, c-Fos is not essential for apoptosis in the rd mouse.
细胞凋亡是光诱导性视网膜变性以及几种视网膜营养不良动物模型中光感受器最终的共同死亡途径。迄今为止，视网膜中细胞凋亡的基因调控情况鲜为人知。即刻早期基因c-fos的表达在光诱导性光感受器变性以及视网膜变性的动物模型rd小鼠中，伴随细胞凋亡而上调。在最近一项研究中发现，c-Fos对于体内光诱导性光感受器细胞凋亡至关重要。为了确定c-Fos是否也参与遗传性视网膜变性的凋亡途径，已培育出rd/rd、c-fos-/-双突变小鼠。
双突变小鼠（rd/rd，c-fos-/-）由c-fos+/-小鼠与rd/rd小鼠杂交培育而成。通过对基因组DNA进行聚合酶链反应分析来确定其基因型。野生型对照小鼠和纯合rd小鼠在出生后第（P）9天至P21天每隔2天处死。双突变小鼠在出生后第P9、P11、P13、P15和P21天处死。为了确定视网膜中的细胞凋亡水平，摘除眼球并进行光学显微镜检查和原位缺口末端标记。从分离的视网膜中提取总视网膜DNA用于DNA片段化分析。
形态学、组织化学和生化分析表明，rd/rd、c-fos-/-双突变小鼠中细胞凋亡的时间进程以及光感受器变性的结果与携带功能性c-fos的rd小鼠并无差异。
这些数据表明，与它在光诱导性光感受器变性中的作用不同，c-Fos对于rd小鼠的细胞凋亡并非必不可少。
