Elucidating the mechanism and consequences of aberrant cyclin D1 gene expression

摘要 有些基因采取严厉措施来迫使其异常表达。例如，基因周期蛋白 D1 通常不存在于 B 细胞淋巴细胞中，但在血癌中表达 套细胞淋巴瘤 （MCL）。 MCL 是所有 B 细胞恶性肿瘤中最具侵袭性的一种染色体易位事件， 在疾病发生之前，激活细胞周期蛋白 D1 启动子是正常细胞转化的起始病变 B 细胞。一旦表达，转录的细胞周期蛋白 D1 信息（前 mRNA）将进行进一步处理 这使其能够缩短其 3' 非翻译区 (3'UTR)，从而增加转录物的半衰期。 MCL 中细胞周期蛋白 D1 的表达促进过度增殖表型并增加遗传性 B 细胞的不稳定和染色体异常。在我们之前的工作中，我们发现了一个新的融合基因 MCL 细胞系和患者样本，其中细胞周期蛋白 D1 与另一个基因连接，从而导致截短 3'UTR。该项目的目标是确定驱动缩短的分子机制 细胞周期蛋白 D1 的 3'UTR 以及细胞周期蛋白 D1 驱动的染色体易位事件的影响。在这个 建议我们将确定如何在细胞周期蛋白 D1 的前体 mRNA 以及蛋白质中发现序列 参与 3' 末端加工的蛋白在优化 MCL 中细胞周期蛋白 D1 的表达方面发挥着作用（目标 1）。我们会 还使用第三种方法系统地鉴定了由染色体易位事件产生的融合基因 一代测序技术使我们能够获得全长基因转录本（目标 2）。虽然 众所周知，MCL 中染色体易位的发生频率很高，除了 个别案例研究中的偶然发现，很少有人致力于识别融合基因 全球规模使此类研究具有创新性。此外，我们的研究将确定分子 异常3'端形成的基础将回答该领域的一个基本问题。这将产生积极影响 通过更好地了解致病基因在人类细胞中的表达，将允许 寻找更有效的策略来检测和治疗疾病。

ABSTRACT Some genes take drastic measures to force their aberrant expression. As an example, the gene cyclin D1 which is not normally present in B-cell lymphocytes is expressed in the blood cancer Mantle Cell Lymphoma (MCL). MCL is the most aggressive of all B-cell malignancies and a chromosomal translocation event, that pre-dates the disease, activates the cyclin D1 promoter is the initiating lesion in the transformation of normal B-cells. Once expressed, the transcribed cyclin D1 message (pre-mRNA) undergoes further processing which enables it to shorten it's 3'untraslated region (3'UTR) thus increasing the half-life of the transcript. The expression of cyclin D1 in MCL facilitates a hyper-proliferative phenotype and increases the genetic instability and chromosomal abnormalities of B-cells. In our prior work we identified a novel fusion gene in MCL cell lines and patient samples where cyclin D1 is joined to another gene thus resulting in a truncated 3'UTR. The goal of this project is to determine the molecular mechanisms that drive the shortening of the 3'UTR of cyclin D1 as well as the effects of the cyclin D1 driven chromosomal translocation events. In this proposal we will determine how the sequences found in the pre-mRNA of cyclin D1 as well as proteins involved in 3'end processing play a role in optimizing the expression of cyclin D1 in MCL (Aim 1). We will also systematically identify fusion genes, which result from chromosomal translocation events, using third generation sequencing technology which allows us to get full length gene transcripts (Aim 2). Although chromosomal translocations are known to occur with a high degree of frequency in MCL, apart from serendipity discovery in individual case studies, little effort has been put into identifying fusion genes on a global scale making this type of research innovative. Furthermore, our study will determine the molecular basis of abnormal 3'end formation will answer a basic question in the field. This will have a positive impact by establishing better understanding of disease causing genes are expressed in human cells and will allow for more effective strategies to detect and treat disease.