INTRACELLULAR LOCALIZATION OF SMALL NUCLEOLAR RNAS

描述（改编自申请人的摘要）：SnoRNA需要 顺式作用的核仁定位元件使其成熟形式保持不变 在分裂间期的核仁中，在分裂末期重组为核仁。 有丝分裂，并迁移到核仁后，他们的生物合成中， 核质 E1，E2和E3 snoRNA不属于主要的类， snoRNA，因为它们不具有存在于大多数snoRNA中的序列。 E1和E2 snoRNA是18 S rRNA形成所必需的， 在体内直接与前体rRNA的独特片段相互作用。 人E1，E2， 和E3 RNA在注射后特异性地定位于核仁 注入青蛙卵母细胞的细胞质中。 根据这些观察，P.I. 提出，这些RNA中的每一个都具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 因素 为了确定核仁的分子机制， 这些snoRNA的定位P.I.将识别出 使用snoRNA突变分析这些snoRNA的定位元件， 全细胞 此外，核仁定位蛋白所需的 这些snoRNA将使用注射的竞争实验来鉴定， 细胞，迁移率变动分析和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.