Trans-Splicing in Drosophila

描述（由申请人提供）： 翻译后摘要：前信使RNA（前mRNA）剪接是一个过程中，内含子被删除，加入外显子在一起。这一过程在几乎所有后生动物mRNA（约93%的人类mRNA）的合成过程中使用，是调节基因表达的重要手段。只有少数例外，剪接发生在顺式-连接在一起的外显子位于相同的前mRNA上。在一些真核生物中，包括线虫、锥虫和真涡虫，剪接可以反式发生。在这些情况下，专门剪接的前导RNA被剪接到蛋白质编码RNA的5 '端。有趣的是，有几种情况下，一个独特的类型的反式剪接已被证明发生，即剪接外显子从蛋白质编码基因。两个最好的表征例子是来自果蝇的mod（mdg 4）和lola基因。在这些基因中的每一个中，一组共同的5 '外显子可以反式剪接到几个（mod（mdg 4）为26个或lola为22个）可变3'外显子中的一个。一个令人信服的反式剪接案例已被证明发生在蚊子身上，最近在人类身上也发现了一个。在这些情况下，偶然发现了这些基因的反式剪接。因此，反式剪接的真实程度是未知的。此外，对反式剪接中涉及的机制一无所知。我们最近使用深度测序来识别果蝇中80个新的反式剪接基因。这个项目的长期目标是进一步探索果蝇中的反式剪接景观，并确定这一过程中涉及的机制。我们将首先进行一个详尽的调查，在不同的果蝇物种的整个发展过程中的反式剪接基因。其次，我们将进行实验来测试反式剪接的mRNA是否被翻译并且是功能性的。最后，这些实验将通过生物化学、遗传学、基因组学、细胞生物学和生物信息学实验的组合来补充，这些实验旨在确定反式剪接发生的机制。这些实验将为反式剪接的机制提供巨大的洞察力，这是一个完全未被研究但重要的过程。考虑到反式剪接在治疗人类疾病方面的潜在效用，以及人类中反式剪接的mRNA最近与癌症有关，我们的发现很可能与人类健康直接相关。

DESCRIPTION (provided by applicant): Abstract: Pre-messenger RNA (pre-mRNA) splicing is a process in which introns are removed to join exons together. This process is used during the synthesis of nearly all metazoan mRNAs (~93% of human mRNAs) and is an important means of regulating gene expression. With only a handful of exceptions, splicing occurs in cis - the exons that are joined together are located on the same pre-mRNA. In some eukaryotes, including nematodes, trypanosomes and planarians, splicing can occur in trans. In these cases, a specialized spliced leader RNA is spliced to the 5' end of protein coding RNAs. Interestingly, there are a few cases where a distinct type of trans-splicing has been shown to occur, namely, the splicing of exons from protein coding genes. The two best characterized examples are the mod(mdg4) and lola genes from Drosophila. In each of these genes, a group of common 5' exons can be spliced in trans to one of several (26 for mod(mdg4) or 22 for lola) variable 3' exons. One convincing case of trans-splicing has been shown to occur in mosquitos and one has been recently shown in humans. In each of these cases, trans-splicing of these genes was discovered fortuitously. As a result, the true extent of trans-splicing is unknown. Moreover, nothing is known about the mechanisms involved in trans-splicing. We have recently used deep sequencing to identify 80 new genes that are trans-spliced in Drosophila. The long- term goals of this project are to further explore the trans-splicing landscape in Drosophila and to determine the mechanisms involved in this process. We will first perform an exhaustive survey for trans-spliced genes throughout development in different Drosophila species. Second, we will perform experiments to test whether the trans-spliced mRNAs are translated and are functional. Finally, these experiments will be complemented by a combination of biochemical, genetic, genomic, cell biology, and bioinformatics experiments designed to determine the mechanisms by which trans- splicing occurs. Together these experiments will provide tremendous insight into the mechanisms of trans-splicing, a completely understudied yet important process. Given the potential utility of trans-splicing in treating human diseases and that trans-spliced mRNAs in humans have recently been linked to cancer, it is likely the discoveries we make will be of direct relevance to human health.