MOLECULAR MECHANISMS IN NEOPLASIA

这个项目的目标是探索致癌的生物学。 逆转录病毒和宿主细胞作为实现更好的 对肿瘤性改变的理解。该项目的重点是病毒 法氏囊淋巴瘤的诱导作为实验系统， 包括B细胞发育的相关方面，免疫球蛋白(Ig) 基因多样化和逆转录病毒复制。具体目标是：(1) 正常和v-myc癌前病变组织中基因表达的检测 法氏囊干细胞(TF细胞)。针对转铁蛋白细胞的单抗将是 表征和开发了额外的抗体。Tf细胞抗体 识别正常法氏囊干细胞将被寻找和候选细胞 通过这种抗体鉴定的人群将接受干细胞检测。 在移植试验中的活性和对 由myc进行的转换。(2)辅助病毒作用的确定 法氏囊淋巴肿大的感染和遗传不稳定性。频次 V-myc诱导癌前转化卵泡(Tf)的进展 对侵袭性淋巴瘤的诊断将取决于是否存在 传染性辅助病毒。转铁蛋白细胞群体对伽马的敏感性 辐射将被定义为相对于正常干细胞和增殖 法氏囊中的细胞群。免疫球蛋白基因的基因转换扰动 将通过聚合酶链式反应技术和 寻找免疫球蛋白中异常的、潜在致癌的重组事件 将进行现场调查。(3)EGF角色的确定 家族样基因在法氏囊间质中高度表达。具体的 表达该基因的基质细胞类型将通过原位确定 杂交。抗体将被用来了解这种蛋白质是否 基因在法氏囊基质细胞表面表达或分泌。 如果是这样的话，它们将在组织培养中通过重组构建物表达 为了确定该基因是否能促进法氏囊上皮的生长， 正常干细胞或培养中的转铁蛋白细胞。(4)确定 反义RNA抑制逆转录病毒复制的机制。 反义RNA可以抑制逆转录病毒的假说将得到检验。 干扰第二链病毒DNA的RNA引物进行复制 综合。将确定末端缺失的病毒DNA的结构 在反义RNA存在下形成的分子。反义的能力 抑制RNase H形成第二链引物的RNA将被 在体外模型系统中进行了测试。

The goal of this project is the exploration of the biology of oncogenic retroviruses and host cells as a strategy for achieving a better understanding of neoplastic change. The project is focussed on viral induction of lymphomas in the bursa of Fabricius as an experimental system, and includes relevant aspects of B-cell development, immunoglobulin (Ig) gene diversification and retroviral replication. Specific aims are: (1) Detection of genes expressed in normal and v-myc induced preneoplastic bursal stem cells (TF cells). Monoclonal antibodies to TF cells will be characterized and additional antibodies developed. TF cell antibodies which recognize normal bursal stem cells will be sought and candidate cell populations identified by such antibodies will be tested for stem cell activity in transplantation assays and for selective sensitivity to transformation by myc. (2) Determination of the roles of helper virus infection and genetic instability in bursal lymphomagenesis. The frequency of progression from v-myc induced preneoplastic transformed follicles (TF) to invasive lymphomas will be determined in the presence and absence of infectious helper virus. The sensitivity of TF cell populations to gamma irradiation will be defined relative to normal stem cell and proliferating cell populations in the bursa. Perturbation of gene conversion at Ig genes in TF cells will be assessed by polymerase chain reaction techniques and a search for abnormal, potentially oncogenic recombination events at Ig loci will be undertaken. (3) Determination of the role of an EGF family-like gene highly expressed in the bursal stroma. The specific stromal cell type expressing this gene will be determined by in situ hybridization. Antibodies will be used to learn if the proteins of this gene are expressed on the surface of bursal stromal cells or are secreted. If so, they will be expressed from recombinant constructs in tissue culture to determine if this gene can enhance the growth of bursal epithelium, normal stem cells or TF cells in culture. (4) Determination of the mechanism of antisense RNA mediated inhibition of retroviral replication. The hypothesis will be tested that antisense RNA can inhibit retroviral replication by interference with the RNA primer for second strand viral DNA synthesis. The structure will be determined of terminally deleted viral DNA molecules formed in the presence of antisense RNA. The ability of antisense RNA to inhibit formation of the second strand primer by RNase H will be tested in an in vitro model system.