DEVELOPMENTAL ROLE OF XERODERMA PIGMENTOSUM RELATED GENE

着色性干皮病 (XP) 和克罗凯恩综合征 (CS) 是人类的疾病 以对紫外线敏感性增加为特征的疾病和 一系列发育和神经系统异常。 此外，XP 患者表现出患皮肤癌的高度易感性。 来自患者的细胞 患有这两种疾病的人都存在核苷酸切除修复（NER）缺陷，并且 属于代表不同基因的多个互补组 NER途径。 额外的工作表明，产品 其中一些 NER 基因作为转录的组成部分具有双重作用 因子 TFIIH。 这些基因产物参与转录 开始解释 XP 突变的多效性效应。 然而， 尽管这些蛋白质在转录中发挥直接作用， 与 XP 相关的异常通常是有限的。 这表明 这些蛋白质可能参与特定的发育决策。 这些 重要的发展进程仍有待确定。 我们建议使用多细胞粘菌 Dictyostelium discoideum 研究 XP 和 CS 相关的特定发育和细胞作用 基因。 虽然相对简单，但盘基网柄菌具有许多共同点 高等真核生物的发育过程。 它的学习方便性 得出了其在细胞和细胞上的发展的详细图片 分子水平。 分子生物学技术，包括那些 同源基因破坏，开发良好，可以轻松构建 以及特定突变体的研究。 可以使用以下方法详细研究表型 广泛的现有技术、探针和抗体。 我们已经鉴定并研究了盘基网柄菌的repE基因，该基因编码 预测产物与人类 UV-DDB（UV 损伤 DNA）同源 结合）蛋白，一些患有以下疾病的患者缺乏 UV-DDB 蛋白 XPE。 预测的repE蛋白编码假定的亮氨酸拉链基序 以及相关的基本区域。 我们制作了repE基因破坏突变体， 并且他们在发展上有一个独特的缺陷。 突变细胞被封锁 多细胞组装体的聚集和形成。 有趣的是， 突变细胞可以表达所有测试过的早期发育基因 获得正常聚集细胞的细胞形态。 然而，迟到了 发育基因不表达。 这些数据表明repE 基因充当连接早期和晚期的特定发育开关 发展。 我们建议旨在分析这一具体方面 发展作用包括； 1）repE的发育调控； 2)repE基因产物的蛋白质和DNA相互作用； 3） 导致表型的生化和细胞生物学缺陷 repE突变体。 我们还鉴定了盘基网柄菌 XPB 和 XPD 基因的同源物 人类存在多种发育缺陷。 我们建议 克隆并破坏这些基因，以便可以发挥它们的发育作用 研究过。 总的来说，我们的数据表明盘基网柄菌在 阐明 XP 和 CS 的特定发育和细胞作用 基因。

Xeroderma pigmentosum (XP) and Crockayne's syndrome (CS) are human disorders that are characterized by increased sensitivity to UV light and a range of developmental and neurological abnormalities. In addition, XP patients show a high predisposition to skin cancer. Cells from patients with both diseases are defective in nucleotide excision repair (NER), and fall into multiple complementation groups that represent different genes of the NER pathway. Additional work has demonstrated that the products of some of these NER genes have dual roles as components of the transcription factor TFIIH. The involvement of these gene products in transcription begins to explain the pleiotropic effects of the XP mutations. However, even though these proteins play a direct role in transcription, the abnormalities associated with XP are generally limited. This suggests that these proteins may be involved in specific developmental decisions. These important developmental processes remain to be identified. We propose to use the multicellular slime mold, Dictyostelium discoideum to study the specific developmental and cellular roles of XP and CS related genes. Although relatively simple, Dictyostelium shares many of the developmental processes of higher eucaryotes. Its ease of study has resulted in a detailed picture of its development at both the cellular and molecular levels. Molecular biology techniques, including those for homologous gene disruption, are well developed allowing facile construction and study of specific mutants. Phenotypes can be studied in detail using a wide range of existing techniques, probes and antibodies. We have identified and studied the Dictyostelium repE gene which encodes a predicted product that is homologous to the human UV-DDB (UV-damaged DNA binding) protein, The UV-DDB protein is absent from some patients with XPE. The predicted repE protein encodes a putative leucine-zipper motif and an associated basic region. We have made repE gene disruption mutants, and they have a unique defect in development. The mutant cells are blocked in aggregation and formation of multicellular assemblies. Interestingly, the mutant cells can express all the early developmental genes tested and acquire the cellular morphology of normal aggregating cells. However, late developmental genes are not expressed. These data suggest that the repE gene acts as a specific developmental switch linking early and late development. We propose aims to analyze specific aspects of this developmental role including; 1) the developmental regulation of repE; 2) the protein and DNA interactions of the repE gene product; and 3) the biochemical and cell biological defects responsible for the phenotype of the repE mutants. We have also identified the Dictyostelium homologs of the XPB and XPD genes which have a variety of developmental defects in humans. We propose to clone and disrupt these genes so that their developmental roles can be studied. Overall, our data indicate that Dictyostelium is useful in elucidating the specific developmental and cellular roles of XP and CS genes.