PROTEIN FACTORS IN U12-DEPENDENT PRE-MRNA SPLICING

描述(改编自申请人的描述)：从 剪接前体mRNA是大多数基因在高等植物中表达的必备条件 真核生物。最近的工作定义了一类罕见但分布广泛的内含子 通过一条不用于典型内含子的替代途径进行拼接。两者都有 主要和次要类的内含子通过类似的机制在 大的核糖核蛋白复合体称为剪接体，但剪接体 对于每一类不同的RNA组成，同时保持高度的 关键的RNA-RNA相互作用的相似性。与大班形成鲜明对比 剪接体，对次要的蛋白质组成知之甚少 类剪接体。这个项目试图调查已知的角色 在小类内含子剪接中主要内含子类的剪接因子， 在重组的剪接系统中主要使用生化方法。 在剪接位点选择的早期步骤中涉及的因素特别 感兴趣，因为这两个内含子类很可能相互通信以 允许正确拼接包含这两种内含子的消息。共享和 将通过亲和力分析鉴定特定类别的剪接体蛋白 选择具有适当抗体的小类剪接体，并通过获得 从纯化的次要类中回收的蛋白质的序列信息 剪接体。

DESCRIPTION (adapted from the applicant's description): Removal of introns from precursor mRNA by splicing is mandatory for expression of most genes in higher eukaryotes. Recent work defined a rare but broadly distributed class of introns that are spliced by an alternative pathway not used for typical introns. Both the major and minor classes of introns are spliced by a similar mechanism in a large ribonucleoprotein complex termed the spliceosome, but the spliceosomes for each class differ in RNA composition while maintaining a high degree of similarity in critical RNA-RNA interactions. By contrast to the major class spliceosome, very little is known about the protein composition of the minor class spliceosome. This project seeks to investigate the roles of known splicing factors of the major intron class in splicing of minor class introns, using primarily biochemical approaches in a reconstituted splicing system. Factos involved in early steps of splice site selection are of particular interest because the two intron classes likely communicate with each other to allow correct splicing of messages containing both kinds of introns. Shared and class-specific spliceosome proteins will be identified by analyzing affinity selected minor class spliceosomes with appropriate antibodies, and by obtaining sequence information for proteins recovered from the purified minor class spliceosomes.