GENES REGULATING APOPTOTIC CELL DEATH IN BURSAL B-CELLS

细胞凋亡是一种基因指导的或程序性的细胞死亡过程， 在多种生物过程中起着重要作用。 为 例如，该途径的调节对两种细胞都有影响， 癌症的发病机制和治疗。 目前人们对这一事件知之甚少。 调节凋亡细胞死亡的基因。 该提案的重点是 正常和肿瘤性B细胞发育在法氏囊作为一个 用于分离和表征这些基因的模型实验系统。 我们最近已经表明，低剂量辐照和机械辐照 囊卵泡中细胞接触的破坏迅速引发 正常胚胎囊滤泡淋巴细胞凋亡。 Myc癌基因诱导的癌前腔上囊干细胞具有高敏感性 诱导细胞死亡，而细胞凋亡被积极抑制， 从这些细胞衍生的肿瘤。 该提案包含三个具体的 目标。 首先，我们计划过度表达凋亡的负调节因子， Bcl-2，在囊细胞中使用逆转录病毒载体。 我们将确定是否 Bcl-2对正常胚胎和/或癌前法氏囊干细胞具有保护作用 以及这种保护作用对细胞凋亡的表型影响。 使用法氏囊在法氏囊中的正常和肿瘤性B细胞发育 移植技术。 其次，我们将cDNA插入病毒载体中， 我们已经从囊细胞类型中制备了细胞凋亡的文库， 似乎受到了积极的抑制。 通过分离病毒， 我们希望克隆保护囊细胞免于凋亡的文库， 表征负调控细胞死亡途径的基因。 第三，如果这种方法似乎是成功的，我们计划选择性的， 筛选来自其他细胞类型和其他物种的cDNA文库， 确定该系统是否可用于在功能上隔离 保守的细胞死亡调控基因。

Apoptosis is a process of gene directed or programmed cell death which plays a significant role in a variety of biological processes. For example the regulation of this pathway has implications for both the pathogenesis and treatment of cancer. Little is yet known about the genes which regulate apoptotic cell death. This proposal focuses on normal and neoplastic B-cell development in the bursa of Fabrcius as a model experimental system for isolating and characterizing such genes. We have recently shown that both low dose irradiation and mechanical disruption of cell contacts in bursal follicles rapidly triggers apoptosis in the total lymphoid of normal embryonic bursal follicles. Myc oncogene induced preneoplastic bursal stem cells are hypersensitive to induction of cell death while apoptosis is actively suppressed in neoplasms derived from such cells. This proposal contains three specific aims. First, we plan to over express a negative regulator of apoptosis, Bcl-2, in bursal cells using a retroviral vector. We will determine if Bcl-2 can protect normal embryonic and/or preneoplastic bursal stem cells from apoptosis and the phenotypic consequences of such protection on normal and neoplastic B-cell development in the bursa using bursal transplantation techniques. Second, we will insert in viral vectors cDNA libraries we have prepared from bursal cell types in which apoptosis appears to be actively suppressed. By isolating viruses from such libraries which protect bursal cells from apoptosis we hope to clone and characterize genes which negatively regulate the cell death pathway. Third, if this approach appears to be successful, we plan selective screening of cDNA libraries from other cell types and other species to determine if this system might be useful for isolating functionally conserved cell death regulatory genes.