GENES REGULATING APOPTOTIC CELL DEATH IN BURSAL B-CELLS

细胞凋亡是一种基因引导或程序性细胞死亡的过程 在各种生物过程中扮演着重要的角色。为 这一途径的调节对两个方面都有影响 癌症的发病机制和治疗。人们对这一现象知之甚少 调控细胞凋亡的基因。这项提案的重点是 法氏囊的正常和肿瘤性B细胞发育 分离和鉴定这类基因的模型实验系统。 我们最近已经证明，低剂量照射和机械照射 法氏囊内细胞接触的中断会迅速引发 正常胚胎法氏囊滤泡全淋巴组织中的细胞凋亡 MYC癌基因诱导的癌前法氏囊干细胞超敏反应 诱导细胞死亡，同时主动抑制细胞凋亡 起源于此类细胞的肿瘤。该提案包含三个具体内容 目标。首先，我们计划过度表达一种负向的细胞凋亡调节因子， 使用逆转录病毒载体在法氏囊细胞中表达bc1-2。我们将确定是否 BCL-2对正常胚胎和/或癌前病变的法氏囊干细胞的保护作用 从细胞凋亡和这种保护的表型后果 法氏囊中正常和肿瘤B细胞的发育 移植技术。第二，我们将在病毒载体中插入c DNA 我们从法氏囊细胞类型中制备的文库中， 似乎受到了积极的压制。通过将病毒从这样的 我们希望克隆和克隆保护法氏囊细胞免受凋亡的文库 描述负向调节细胞死亡途径的基因。 第三，如果这种方法看起来是成功的，我们计划选择性地 从其他细胞类型和其他物种中筛选cDNA文库以 确定此系统是否可用于功能隔离 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.