EXPRESSION AND FUNCTION OF U1 RNA ISOFORMS DURING DEVELOPMENT

此续期申请中描述的研究代表 在过去的7年里，我们在这个项目上继续努力。这个 我们项目的中心主题是结构和功能 U1相关序列及其转录本的特征 蚕蛾、家蚕。这个科学计划已经起到了作用，也将起到作用 继续成为教育和激励有前途的少数群体的工具 学生追求生物医学科学的职业生涯。U1 RNA是一种 六个丰富的小核RNA(SnRNAs)，U1-U6，已知 与六到十种蛋白质相联系。这些RNA/蛋白质复合体形成 在剪接中起作用的小核糖核蛋白颗粒(SnRNP) HnRNA转化为信使核糖核酸。我们的实验室有三个结构特征 蚕蛾U1相关序列的分类。其中一类是 由能够组装成的异构体或变体组成的 具有免疫活性的U1 SNRNPs。第二个类由 假基因和第三组由高度重复的U1- 相关序列家族，我们将其标记为Bm1。U1变种和Bm1 重复元件是发育和组织特有的 转录表明在基因表达中起到了控制作用。这 Proposal描述了旨在阐明U1和SnRNP角色的实验 蛋白质变异体在基因表达的控制中发挥作用。它们的功能 在hnRNA剪接中，将使用发育阶段的丝素进行研究 腺体、滤泡和几个家蚕细胞系。U1亚型先前 我们实验室的特性将用于重建实验 其中它们差异组装成SnRNP/hnRNP颗粒，它们 含内含子的丝素蛋白和绒毛膜RNA及其相互作用 将确定拼接能力。这些研究应该有助于确定 U1的发育和组织特异性表达的可疑作用 差异剪接和发育中的变体。由于普遍存在的 以及所问问题的中心性质，以及所获得的答案 在这些实验过程中可能会有深刻的生物医学 这意味着什么。

The research described in this renewal application represents the continuation of our efforts on this project over the past 7 years. The central theme of our project has been the structural and functional characterization of U1-related sequences and their transcripts in the silkmoth, Bombyx mori. This scientific program has served and will continue to be a vehicle to educate and motivate promising minority students to pursue careers in the biomedical sciences. U1 RNA is one of six abundant small nuclear RNAs (snRNAs), U1-U6, which are known to associate with six to ten proteins. These RNA/protein complexes form small ribonucleoprotein particles (snRNPs) which function in splicing hnRNA into mRNA. Our laboratory has structurally characterized three categories of U1-related sequences in the silkmoth. One category is comprised of isoforms or variants capable of assembling into immunologically active U1 snRNPs. A second class is represented by pseudogenes and the third group is composed of a highly reiterated U1- related sequence family which we labelled Bm1. The U1 variants and Bm1 repetitive elements are developmentally and tissue specifically transcribed suggesting a role in control of gene expression. This proposal describes experiments designed to elucidate the role U1 and snRNP protein variants play in the control of gene expression. Their function in hnRNA splicing will be investigated using developmentally staged silk glands, follicles and several B. mori cell lines. U1 isoforms previously characterized in our laboratory will be used in reconstitution experiments in which their differential assembly into snRNP/hnRNP particles, their association with intron-containing fibroin and chorion RNAs and their splicing capacities will be ascertained. These studies should help define the suspected role of developmental and tissue-specific expression of U1 variants in differential splicing and development. Due to the universal and central nature of the questions being asked, the answers obtained during the course of these experiments may have profound biomedical implications.