FUNCTIONS OF SMALL NUCLEOLAR RNAS

核糖体生物发生是细胞生物学中的基本过程，但很少 了解其机制。E1、E2和E3小核仁RNA （snoRNA）不属于最知名的snoRNA类别，因为它们 缺少那些snoRNA中存在的序列。 这三 snoRNA直接与核糖体RNA的独特片段相互作用 前体（pre-rRNA）。这三种snoRNA中的每一种的降解 产生独特的青蛙卵母细胞前rRNA加工表型， 被相应的snoRNA逆转。 E1和E2 RNA对于 18 S rRNA形成。 这些snoRNA中的每一个都具有独特的保守的 序列的根据现有的结果，我们建议，这些 snoRNA：a）至少参与前rRNA加工， 在pre-rRNA切割位点之后，E1在5'端，E2在3'端 5.8SrRNA的5'端为E3， 序列;和B）具有新的，可能是唯一的顺式作用结构域， rRNA加工可能与新的蛋白质相互作用， 功能协调发展的 长期目标：确定 E1、E2和E3小核仁核糖核蛋白的功能 核糖体形成中的颗粒。 我们的具体目标是：1）鉴定snoRNA的顺式作用元件 这些snoRNA在pre-rRNA加工中的功能所需，2） 确定这些snoRNA结构域与蛋白质的相互作用， rRNA和其他snoRNA，这是功能所需的，3）测试的 这些功能的模型集中在这些snoRNA元件上， 相互作用，以及4）开发无细胞前rRNA加工系统 其依赖于外源E1或E2 RNA。 会来做这项工作 snoRNA突变分析，迁移率变动分析，RNA-蛋白 光交联，反义2 '-0-甲基寡核糖核苷酸 竞争，以及snoRNA和pre-rRNA补偿突变分析， 注射青蛙卵母细胞和转染的哺乳动物细胞。 E2 RNA基因 位于层粘连蛋白结合蛋白基因的内含子中， 在肿瘤侵袭和转移中重要。

Ribosome biogenesis is a fundamental process in cell biology but little is known about its mechanism. E1, E2 and E3 small nucleolar RNAs (snoRNAs) do not belong to the best known class of snoRNAs since they lack the sequences that are present in those snoRNAs. These three snoRNAs interact directly with unique segments of ribosomal RNA precursor (pre-rRNA) in vivo. Degradation of each of these three snoRNAs produces a unique frog oocyte pre-rRNA processing phenotype that is reversed by the corresponding snoRNA. El and E2 RNAs are essential for 18S rRNA formation. Each of these snoRNAs has unique conserved sequences. Based on the available results, we propose that these snoRNAs: a) are at least involved in pre-rRNA processing at the following pre-rRNA cleavage sites, E1 at the 5' end and E2 at the 3' end of the 18S rRNA sequence, and E3 at the 5' end of the 5.8S rRNA sequence; and b) have novel, and probably unique, cis-acting domains for rRNA processing that may interact with novel proteins for their functions. Long-term goal: To determine the molecular mechanisms of the functions of the E1, E2, and E3 small nucleolar ribonucleoprotein particles in ribosome formation. Our Specific Aims are 1) to identify the snoRNA cis-acting elements needed for the functions of these snoRNAs in pre-rRNA processing, 2) to identify the interactions of these snoRNA domains with proteins, pre- rRNA and other snoRNAs, that are required for function, 3) to test the models of these functions focused on these snoRNA elements and these interactions, and 4) to develop cell-free pre-rRNA processing systems that are dependent on exogenous El or E2 RNA. This will be done by snoRNA mutation analysis, mobility shift assay, RNA-protein photocrosslinking , antisense 2'-0-methyloligoribonucleotide competition, and snoRNA and pre-rRNA compensatory mutation analysis, in injected frog oocytes and transfected mammalian cells. The E2 RNA gene lies in an intron of the gene for a lamininbinding protein that is important in tumor invasion and metastasis.