SPLICING OF GROUP II AND GROUP III INTRONS

该项目是对结构、功能和剪接的研究 第II和第III族内含子和双内含子的作用机制 纤细眼虫(Euglena Gracilis)叶绿体基因组的内含子内含子 以及相关的原生生物。这些生物是已知的最丰富的 第二组内含子，具有唯一已知的第二组和第三组 双曲子。具体目标包括：(1)小说的人物塑造 第II和第III组内含子和双内含子 Euglena gracilis作为一种手段来探索(I)可能的 内含子侵袭，(Ii)组II和组III是否共用一个 RNA剪接所需的常见保守结构基序；(2) 研究第三类内含子调味的作用，以及(3) 第II和第III组损伤的顺式作用结构域分析 在体内剪接转基因一号叶绿体所必需的。 这一目标将扩大到包括内含子的定点突变 如果在叶绿体转化方面有足够的技术进步，就会成熟 已实现。这项工作致力于理解基本问题 关于内含子和双内含子的起源和进化。一名工作人员 假设第二组和第三组内含子，以及核 前信使核糖核酸剪接体损伤，可能都有共同的进化 祖先。因此，在最小的变异中研究不寻常的变异 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.