INTRACELLULAR LOCALIZATION OF SMALL NUCLEOLAR RNAS

描述(改编自申请人的摘要)：snoRNAs需要 顺式作用核仁定位元件使其成熟形式保持不变 在间期的核仁中，在末期重组为核仁 有丝分裂，并在其生物合成后迁移到核仁 核质。E1、e2和e3 snoRNAs不属于 因为它们不具有大多数snoRNAs中存在的序列。 E1和e2 snoRNAs对18S rRNA的形成和三个RNAs是必不可少的 在体内直接与Pre-rRNA的独特片段相互作用。人类的E1，E2， 而E3 RNA在注射后特异性地定位于核仁 进入青蛙卵母细胞的细胞质。基于这些观察，P.I. 提出每个RNA都有新的顺式作用核仁 与新的反式作用定位相互作用的定位结构域 各种因素。确定核仁的分子机制 这些snoRNAs的定位P.I.将识别核仁 应用snoRNA突变分析对这些snoRNAs进行定位 整个细胞。此外，核仁定位蛋白所需的 这些snoRNAs将通过注射中的竞争实验进行鉴定 细胞、迁移率变化分析和RNA-蛋白质交联研究。

DESCRIPTION (Adapted from the applicant's abstract): SnoRNAs require cis-acting nucleolar localization elements for their mature form to remain in the nucleolus during interphase, to regroup as a nucleolus at the end of mitosis, and to migrate to the nucleolus after their biosynthesis in the nucleoplasm. E1, E2, and E3 snoRNAs do not belong to the main class of snoRNAs since they do not have sequences that are present in most snoRNAs. E1 and E2 snoRNAs are essential for 18S rRNA formation and the three RNAs interact directly in vivo with unique segments of pre-rRNA. Human E1, E2, and E3 RNAs specifically localize to the nucleolus after they are injected into the cytoplasm of frog oocytes. Based upon these observations, the P.I. proposes that each of these RNAs have novel cis-acting nucleolar localization domains that interact with novel trans-acting localization factors. To determine the molecular mechanisms of the nucleolar localization of these snoRNAs the P.I. will identify the nucleolar localization elements of these snoRNAs using snoRNA mutational analysis in whole cells. In addition, the nucleolar localization proteins needed by these snoRNAs will be identified using competition experiments in injected cells, mobility shift assays and RNA-protein crosslinking studies.