Testing the Reverse-splicing Model of Intron Spread with rDNA Genes

测试 rDNA 基因内含子扩散的反向剪接模型

• 批准号: 0110252
• 负责人: Debashish Bhattacharya
• 金额: $ 39.98万
• 依托单位: University of Iowa
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-10-01 至 2004-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0110252&HistoricalAwards=false
• 关键词: Testing; Reverse; splicing; Model; Intron

A grant has been awarded to Dr. Debashish Bhattacharya at the University of Iowa to determine how intervening sequences (so-called "introns") spread into novel sites in genes. Introns compose a significant portion of genomes (about 16% in humans) and play important roles in gene expression and disease, yet their means of spread remains unknown. This is because few proven cases of recent and widespread intron spread have been documented. The finding of a wealth of recently inserted introns in the ribosomal (r)RNA genes of Euascomycetes fungi makes these organisms ideal for the study of intron spread. Previous work shows that a good candidate for the mechanism by which introns get incorporated into genes is by reversal of the splicing process. The rRNAs of a diverse group of Euascomycetes will be studied to test predictions of the "reverse-splicing" model such as the expectation that introns are preferentially retained at target gene sequences that have a high affinity for splicing factors and that introns are non-randomly distributed, with most of them clustering in regions that are not buried in RNA tertiary structure. Introns play important roles in the evolution of eukaryotic genomes and are implicated in diseases. For example, about 15% of point mutations that are linked to human genetic disease cause defects in the splicing of introns. It is surprising, therefore, that no general model of intron spread exists. In this grant, the recent finding of widespread introns in the nuclear rDNA of Euascomycetes fungi is exploited to address the issue of intron spread. An important strength of the fungal system is the availability of robust secondary and tertiary rRNA structures. This allows the testing of the role of RNA structure in determining intron distribution, an analysis that cannot be done with most pre-mRNAs which have largely unknown folding properties.

爱荷华大学的Debashish Bhattacharya博士获得了一笔拨款，以确定干预序列（所谓的“内含子”）如何扩散到基因的新位置。内含子构成了基因组的很大一部分（在人类中约占16%），在基因表达和疾病中起着重要作用，但它们的传播途径尚不清楚。这是因为很少有证据证明最近广泛的内含子传播的病例被记录下来。在真丝菌真菌的核糖体(r)RNA基因中发现了大量最近插入的内含子，使这些生物成为研究内含子传播的理想场所。先前的工作表明，内含子被整合到基因中的一个很好的候选机制是通过剪接过程的逆转。本研究将研究多种真囊菌的rnas，以验证“反向剪接”模型的预测，如内含子优先保留在对剪接因子具有高亲和力的靶基因序列上，内含子是非随机分布的，其中大多数聚集在未埋在RNA三级结构中的区域。内含子在真核生物基因组的进化中起着重要的作用，并与疾病有关。例如，大约15%与人类遗传疾病有关的点突变会导致内含子剪接缺陷。因此，令人惊讶的是，不存在内含子扩散的一般模型。在这项资助中，最近在真丝菌真菌的核rDNA中广泛发现的内含子被用来解决内含子传播的问题。真菌系统的一个重要优势是强大的二级和三级rRNA结构的可用性。这允许测试RNA结构在确定内含子分布中的作用，这是大多数前mrna无法进行的分析，因为它们具有很大程度上未知的折叠特性。