Department of Cell Biology, University Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd, BMSB 781, Oklahoma City, OK 73104, USA.
Exp Eye Res. 2010 Aug;91(2):186-94. doi: 10.1016/j.exer.2010.04.017. Epub 2010 May 4.
RDS (retinal degeneration slow) is a photoreceptor-specific tetraspanin protein required for the biogenesis and maintenance of rod and cone outer segments. Mutations in the Rds gene are associated with multiple forms of rod- and cone-dominant retinal degeneration. To gain more insight into the mechanisms underlying the regulation of this gene, the identification of regulatory sequences within the promoter of Rds was undertaken. A 3.5 kb fragment of the 5' flanking region of the mouse Rds gene was isolated and binding sites for Crx, Otx2, Nr2e3, RXR family members, Mef2C, Esrrb, NF1, AP1, and SP1 in addition to several E-boxes, GC-boxes and GAGA-boxes were identified. Crx binding sequences were conserved in all mammalian species examined. Truncation expression analysis of the Rds promoter region in Y-79 retinoblastoma cells showed maximal activity in the 350 bp proximal promoter region. We also show that inclusion of more distal fragments reduced promoter activity to the basal level, and that the promoter activities are cell-type and direction specific. Co-transfection with Nrl increased promoter activity, suggesting that this gene positively regulates Rds expression. Based on these findings, a relatively small fragment of the Rds promoter may be useful in future gene transfer studies to drive gene expression in photoreceptors.
RDS（视网膜退行性缓慢）是一种光感受器特异性四跨膜蛋白，对于棒状和锥状外节的生物发生和维持是必需的。Rds 基因的突变与多种棒状和锥状主导的视网膜变性有关。为了更深入地了解该基因调控的机制，对 Rds 启动子内的调节序列进行了鉴定。分离了小鼠 Rds 基因 5'侧翼区的 3.5 kb 片段，并鉴定了 Crx、Otx2、Nr2e3、RXR 家族成员、Mef2C、Esrrb、NF1、AP1 和 SP1 的结合位点，此外还有几个 E 盒、GC 盒和 GAGA 盒。在所有检查的哺乳动物物种中，Crx 结合序列都是保守的。在 Y-79 视网膜母细胞瘤细胞中对 Rds 启动子区域进行截断表达分析显示，在 350 bp 近端启动子区域具有最大活性。我们还表明，包含更远端片段会降低启动子活性至基础水平，并且启动子活性具有细胞类型和方向特异性。与 Nrl 共转染会增加启动子活性，表明该基因正向调节 Rds 表达。基于这些发现，Rds 启动子的一个相对较小的片段可能在未来的基因转移研究中用于驱动光感受器中的基因表达是有用的。
