Molecular Genetics of Color Vision

这项提案的长期目标是充分定义分子 人类色觉的遗传学及其常见缺陷，并阐明 X连锁红绿色视觉的表达调控机制 轨迹。在这一点上存在着显著的基因和表型的异质性 由于长波的常见光谱变种的存在而产生的轨迹 引起各种色觉的敏感(L)和中波(M)色素 缺陷。初步研究表明，一些携带三种形式的女性 其中L和M色素基因具有额外的辨色能力。我们 将调查这种延长的颜色辨别能力的遗传基础。 利用人视网膜母细胞瘤细胞系WEI，我们发现甲状腺 激素调节L和M等几个色素基因的表达 参与光感受器发育和/或人类视网膜疾病。 我们计划使用甲状腺激素受体在体内验证这些发现。 (tr？2)基因敲除小鼠。我们将进行表达微阵列分析 这些处于不同发育阶段的小鼠的视网膜。这样做的结果 分析将确定起调节作用的中间基因(S) 视蛋白基因在发育过程中的表达。 我们发现了M-色素基因上游的一个有趣的区域 与已被证明控制基因表达的绝缘体同源。 这个潜在绝缘子区域的一个多态性与人类L相关：M 锥体比。我们将测试这样一种假设，即这实际上是一种扮演着 L视锥蛋白和M视锥视蛋白表达的重要调节因子此外，我们还将 通过以下方式定义和描述该基因座的所有其他调控区域 高分辨率/高通量DNase I超敏扫描。这些研究 将为调控的分子机制提供新的见解 光感受器基因，进而有助于理解这种关系 基因表达缺陷和视网膜疾病之间的关系。这也将有助于 开发针对细胞的基因治疗策略。

The long-term objectives of this proposal are to fully define the molecular genetics of human color vision and its common defects, and to elucidate the mechanisms of regulation of expression of the X-linked red-green color vision locus. A remarkable heterogeneity of genotypes and phenotypes exist at this locus due to the existence of common spectral variants of the long wave sensitive (L) and middle wave sensitive (M) pigments causing various color vision defects. Preliminary studies have shown that some women who carry three forms of the L and M pigment genes have additional color discrimination capacity. We will investigate the genetic basis for this extended color discrimination capacity. Using the human retinoblastoma cell line WERI, we found that thyroid hormone regulates expression of the L and M pigment genes plus several others that are involved in photoreceptor development and/or human retinal diseases. We plan to validate these findings in vivo using a thyroid hormone receptor ¿2 (TR¿2) knockout mouse. We will perform expression microarray anslysis in the retinas of these mice at different stages of development. The results of this analysis will identify the gene(s) that acts as an intermediate in regulation of opsin gene expression by TR¿2 during development. We identified an interesting region upstream of the M-pigment gene which is homologous to ¿insulators¿ that have been shown to control gene expression. A polymorphism in this potential ¿insulator¿ region is associated with human L:M cone ratio. We will test the hypothesis that this is really an insulator that plays an important regulator of expression of the L and M cone opsins. In addition, we will define and characterize all of the rest of the regulatory regions of this locus by high resolution/high throughput DNase I hypersensitivity scans. These studies will provide new insights into the molecular mechanisms of regulating photoreceptor genes, and in turn will help in understanding the relationship between defects in gene expression and retinal disease. This will also help in developing cell-specific gene therapy strategies.