EXPRESSION AND FUNCTION OF U1 RNA ISOFORMS DURING DEVELOPMENT

本更新申请中描述的研究代表了 这是我们在过去7年里为这个项目所做的努力。 的 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 家蚕 这项科学计划已经并将 继续作为教育和激励有前途的少数民族的工具 学生追求职业生涯中的生物医学科学。 U1 RNA是一种 六种丰富的小核RNA（snRNA），U1-U6，已知它们 与6到10种蛋白质结合。 这些RNA/蛋白质复合物形成 在剪接中起作用的小核糖核蛋白颗粒（snRNP） hnRNA转化为mRNA。 我们的实验室在结构上表征了三个 家蚕U1基因相关序列的分类。 一类是 由能够组装成 免疫活性U1 snRNP。 第二类表示为 假基因和第三组是由一个高度重复U1- 我们标记为Bm 1的相关序列家族。 U1变体和Bm 1 重复的元素是发育和组织特异性的 转录表明在控制基因表达中的作用。 这 该提案描述了旨在阐明U1和snRNP作用的实验 蛋白质变体在基因表达的控制中起作用。 它们的功能 在hnRNA剪接将研究使用发育阶段丝 腺体、滤泡和几个B. Mori细胞系。 以前的U1亚型 在我们的实验室表征将用于重构实验 其中它们差异组装成snRNP/hnRNP颗粒，它们 与含内含子的丝心蛋白和绒毛膜RNA及其 将确定拼接能力。 这些研究有助于确定 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 和中心性质的问题被问到，得到的答案 在这些实验的过程中， 影响

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.