BIOLOGY OF HUMAN RETROTRANSPOSITION

人类逆转录转座生物学

• 批准号: 2568986
• 负责人: G SWERGOLD
• 金额: --
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/2568986
• 关键词: Polyomavirus hominis 2; T cell receptor; cis platinum compound; drug resistance; gel mobility shift assay; gene mutation; genetic enhancer element; germ cell neoplasms; human genetic material tag; human immunodeficiency virus; messenger RNA; molecular cloning; neoplasm /cancer genetics; nucleic acid repetitive sequence; nucleic acid sequence; teratoma; tissue /cell culture; transcription factor; transposon /insertion element; virus genetics

The human genome contains 100,000 fragments of a repetitive element called the LINE-1 element (L1Hs). Approximately 4,000 of these contain the full 6.2 kb sequence. About 5-10% of the human genome is composed of L1Hs DNA. L1Hs is a retrotransposon that causes insertional mutagenesis upon transposition into sensitive genomic loci. Examples of both somatic and presumed germ-line insertional mutagenesis events caused by L1Hs have been reported. Transposition of the human LINE-1 element (L1Hs) proceeds via an RNA intermediate. Regulation of the transcription of L1Hs is, therefore, the first level of the control of L1Hs transposition. Transcription of L1Hs is tightly regulated. No L1Hs mRNA is observed in most human tissue culture cell lines but transcripts are present in teratocarcinoma cells and in many testicular germ cell tumors. We have continued our investigations of the regulation of L1Hs expression. Previously, we demonstrated that the regulatory signals for the appropriate expression of L1Hs are located entirely within the elements' 5' UTR and that sequences within the first 100 base pairs were most important. Recently we identified teratocarcinoma specific and non cell-specific regulatory elements within the region of bp 60-100. A series of mutations were made that indicated an important role for this region in L1Hs expression. Electro-mobility shift assays revealed at least 6 complexes formed by the binding of nuclear proteins to sequences between bp 60-100. One of the bands was formed by the binding of the ubiquitous Oct 1 protein. Other complexes were specific for embryonal carcinoma cells. We have also continued our investigation of a 140 bp L1Hs enhancer that lies between bp 385-525. We have found that this enhancer shares sequence and organization with important regions of the T-cell receptor a enhancer, and the regulatory regions of HIV and JC Virus. We have continued our efforts to investigate the contribution of isochromosome 12p to the expression of L1Hs. Iso 12p is a feature of both testicular germ cell tumors and the Pallister-Killian Syndrome. In so doing we have developed new methods for expression cloning. These methods are also applicable to identifying and cloning drug resistance genes and we have used them successfully in a model system. We have initiated an effort to clone genes that induce resistance to cis-platin, an important chemotherapeutic agent.

人类基因组包含 100,000 个重复元件片段 称为 LINE-1 元素 (L1Hs)。 其中大约 4,000 个包含 完整的 6.2 kb 序列。 人类基因组的大约 5-10% 是由 L1Hs DNA。 L1Hs 是一种逆转录转座子，可导致插入 转座到敏感基因组位点后发生诱变。 的例子 体细胞和推测的种系插入突变事件引起 L1Hs 已报道。 人类 LINE-1 元件的转座 (L1Hs) 通过 RNA 中间体进行。 转录调控 因此，L1Hs 的控制是 L1Hs 控制的第一级 换位。 L1Hs 的转录受到严格调控。 无 L1Hs mRNA 在大多数人类组织培养细胞系中都观察到，但转录本是 存在于畸胎癌细胞和许多睾丸生殖细胞肿瘤中。 我们继续对 L1H 的监管进行调查 表达。之前，我们证明了监管信号 L1Hs 的适当表达完全位于 元素的 5' UTR 以及前 100 个碱基对内的序列 最重要的是。 最近我们发现了畸胎癌特异性和非特异性 bp 60-100 范围内的细胞特异性调控元件。 一个 一系列突变的发生表明了这一点的重要作用 L1Hs 表达区域。 电动迁移率测定揭示于 核蛋白与序列结合形成至少 6 个复合物 60-100bp之间。 其中一条带是通过结合形成的 普遍存在的 Oct 1 蛋白。 其他复合物对胚胎具有特异性 癌细胞。 我们还继续对 140 bp 进行调查 L1Hs 增强子位于 bp 385-525 之间。 我们发现这 增强子与重要区域共享序列和组织 T 细胞受体增强子以及 HIV 和 JC 的调节区域 病毒。我们继续努力调查 等染色体 12p 与 L1Hs 的表达有关。 ISO 12p 的一个特点是 睾丸生殖细胞肿瘤和帕利斯特-基利安综合征。 在 这样我们就开发出了表达克隆的新方法。 这些 该方法也适用于鉴定和克隆耐药性 基因，我们已经在模型系统中成功地使用了它们。 我们有 发起了克隆诱导顺铂抗性基因的努力， 一种重要的化疗药物。