MOLECULAR MECHANISMS OF CHROMOSOME CHOICE

染色体选择的分子机制

• 批准号: 6498842
• 负责人: WILLIAM M STRAUSS
• 金额: $ 23.12万
• 依托单位: BETH ISRAEL DEACONESS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-02-01 至 2002-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6498842
• 关键词: RNA methylation; RNase protection assay; artificial chromosomes; chemical stability; chromosomes; developmental genetics; embryonic stem cell; fluorescent in situ hybridization; gene expression; gene interaction; gene mutation; genetic transcription; laboratory mouse; messenger RNA; methyltransferase; molecular dynamics; northern blottings; nucleic acid hybridization; nucleic acid probes; nucleic acid sequence; nucleic acid structure; polymerase chain reaction; sex chromosomes; southern blotting

DESCRIPTION (Adapted from investigator's abstract): The goal of this project is to define the mechanism that determines Xist mRNA stability. Based on previous work by the investigator, the structure of the murine Xist gene has been revised to include new information on the 3' end of the gene. The investigator has shown that this area of the gene is significantly larger than previously reported. Sequence comparison between mouse and human revealed sequence similarity in the new 3' ends. Using both Northern analysis and RNAse protection experiments, the investigator has confirmed that both Xist mRNA isoforms are produced by a mechanism involving differential polyadenylation. These polyadenylation sites are located in the new 3' sequences identified. Additional expression studies have shown that Xist mRNA isoforms are developmentally regulated, and therefore show different stabilities. This pattern of expression suggests that regulatory elements may interact differentially with each mRNA isoform, which in turn may influences Xist expression early in development. The data suggest that Xist mRNA isoforms change independently of Tsix and that the developmental regulation of the Xist isoforms is influenced by mRNA stabilization during the period in which upregulation of the chosen X chromosome is observed. The specific mechanism responsible for Xist stability remains poorly characterized. Although early in development Xist is unstable, after development Xist is exceptionally stable (T1/2 = >5 hr). Recent data have placed in doubt the importance of the 5' end of Xist in this regulation. The investigator plans to explore the role of the new 3' end of Xist in gene stability. He also proposes to pursue the mechanism of developmental regulation of Xist stability from two directions. First, a complete a mutational analysis of Xist and the regions immediately adjacent to Xist will be done. Second, the investigator plans to evaluate genes in the methylation pathway and define their role in determining Xist mRNA stability.

描述（根据调查员的摘要改编）：该项目的目的是 定义确定XIST mRNA稳定性的机制。基于以前的 研究人员的工作，鼠xist基因的结构已经 修订以包括有关基因3'末端的新信息。调查员 已经表明，基因的该区域明显大于以前 报告。小鼠和人之间的序列比较揭示了序列 新3'端的相似性。使用北方分析和RNase 保护实验，研究人员已经确认两个Xist mRNA 同工型是通过涉及差异聚腺苷酸化的机制产生的。 这些聚腺苷酸位点位于已确定的新3'序列中。 其他表达研究表明，Xist mRNA同工型是 在开发方面受到监管，因此显示出不同的稳定性。这 表达模式表明调节元素可能相互作用 用每个mRNA同工型差异化，这可能会影响xist 发育早期的表达。数据表明Xist mRNA同工型 独立于TSIX和XIST的发展调节而改变 同工型受mRNA稳定的影响 观察到所选X染色体的上调。 负责XIST稳定性的具体机制仍然很差 特征。虽然开发的早期Xist是不稳定的，但是 开发XIST非常稳定（T1/2 => 5小时）。最近的数据有 疑问，在本法规中，Xist 5'末端的重要性。这 研究者计划探索新的3'Xist在基因中的作用 稳定。他还建议追求发展法规的机制 XIST稳定性来自两个方向。首先，完整的突变分析 XIST和紧邻XIST的区域将完成。第二， 研究者计划评估甲基化途径中的基因并定义 它们在确定XIST mRNA稳定性中的作用。