SPLICING OF GROUP II AND GROUP III INTRONS

本项目是一个研究的结构，功能，和拼接 第二组和第三组内含子和双内含子的机制 （“内含子内内含子”）的质粒基因组的纤细眼虫 和相关的原生生物 这些生物是已知的最丰富的 II组内含子，并且具有唯一已知的II组和III组 双胞胎 具体目标包括：（1）小说人物塑造 组II和组III内含子和双内含子相关的物种 Euglena gracilis作为一种手段，探讨（一）可能的“创始人”事件的 内含子入侵，（ii）组II和组III内含子是否共享一个内含子， RNA剪接所需的共同保守结构基序;（2） 第三组内含子剪接作用的研究，以及（3） II类和III类内含子顺式作用结构域的分析 所需的体内剪接在转基因I。纤细草叶绿体。 这一目标将扩大到包括内含子的定点突变 成熟酶，如果在质体转化方面有足够的技术进步， 办妥了一批 这项工作是为了了解基本问题 关于内含子和双内含子的起源和进化 一个工作 假设II组和III组内含子以及核 前体mRNA剪接体内含子，可能都有一个共同的进化 祖 因此，研究最小的 第二组和第三组内含子应该与理解 RNA结构是所有剪接反应的核心。

This project is a study of the structure, function, and splicing mechanisms of the group II and group III introns and twintrons ("introns-within-introns") of the plastid genomes of Euglena gracilis and related protists. These organisms are the richest known source of group II introns, and have the only known group II and group III twintrons. The specific aims include: (1) Characterization of novel group II and group III introns and twintrons in species related to Euglena gracilis as a means to explore (i) possible "founder" events of intron invasion, (ii) whether group II and group III intorns shared a common conserved structural motifs required for RNA splicing; (2) An investigation of the role of the group III intron spicing, and (3) Analysis of cis-acting domains of group II and group III intorns required for in vivo splicing in transgenic I. gracilis chloroplasts. This aim will be expanded to include site-directed mutagenesis of intron maturases if sufficient technical progress in plastid transformation is achieved. This work is addressed at understanding fundamental questions about the origins and evolution of introns and twintrons. A working hypothesis is that group II and group III introns, as well as nuclear pre-mRNA spliceosomal intorns, may have all shared a common evolutionary ancestor. Therefore, studies on unusual variants among the smallest group II and group III introns should be relevant to understanding the RNA structures at the heart of all splicing reactions.