STRUCTURE AND FUNCTION OF ONCOGENES AND ANTI-ONCOGENES

我们的研究目标是了解分子结构和 在恶性肿瘤、细胞中起关键作用的基因的功能 生长和正常分化。我们关注的是一群 已知癌基因和抑癌基因：C-myc、abl、cbl、bcl2 家族、ras家族和p53、p21(Waf)、p107以及潜在的 小鼠癌基因PVT-1与蛋白激酶C亚型的关系 以及人体组织和肿瘤。我们和其他人已经证明 C-myc继发于染色体的非调控表达 C-myc区的易位是一种重要因素。 与浆细胞瘤发生有关的一系列基因改变 在BALB/c小鼠和Burkitt以及人类艾滋病相关淋巴瘤中。一个 这些激活myc的易位的“变异型”亚群发生 C-myc约260kb 3‘，位于一个命名为pvt-1的区域。我们有 表明这些变异易位中的大多数会导致合成 包括Pvt-1部分和常量的嵌合mRNA Kappa Ig轻链的区域。这种嵌合产品可能会发挥一种 在浆细胞瘤发生或增加c-myc表达中的作用。 我们已经证明BALB/c小鼠在一种特殊的 切除修补的形式。这种缺陷只表现在DNA的修复上 Pvt-1、c-myc、Switch IgA和Ig kappa恒定区的损伤 基因，即重复性染色体易位的位置 小鼠和人类B淋巴细胞肿瘤。这种切除修复的形式 也不同寻常的是，它没有连接到RNA转录，这是 对于大多数形式的DNA切除修复来说都是如此。 我们已经制造出一种表达v-abl和c-abl的重组逆转录病毒。 MYC(ABL-MYC)。这种病毒在100%的人中迅速诱导浆细胞瘤 Balb/c小鼠。如果在感染ABL-MYC之前对小鼠进行免疫， 大约50%的浆细胞瘤产生的抗体是 直接指向免疫原。这项技术已经被用来 产生针对颗粒、蛋白质和多肽的单抗 抗原，它提供了杂交瘤技术的替代方案。这 如果免疫的小鼠B淋巴细胞被感染，方法也有效 体外培养并移植到同基因宿主体内。我们已经证明这一点 癌基因的组合是独特的，因为它允许分化 在没有T细胞帮助的情况下，B细胞转化为浆细胞，在 没有Pristane引发，在没有辅助病毒的情况下。 因为T细胞在浆细胞瘤的诱导过程中不是必需的 有了这种逆转录病毒，我们能够证明T淋巴细胞实际上 延缓这些肿瘤的出现。 我们已经克隆了PKC家族的八种同工酶并进行了表达 载体和产生的细胞系过表达这些 NIH3T3成纤维细胞中的亚型。免疫组织化学研究表明 当每种异构体转移到不同的细胞内细胞器时 被佛波醇酯激活，表明每个底物 异构体仅限于这些位点。我们已经研究了 PKC亚型在淋巴细胞生长发育中的作用。浆细胞瘤 在体内和体外通常依赖于IL-6，我们有 确定了IL-6的退出通过细胞凋亡导致细胞死亡。 佛波醇可以延缓这种细胞凋亡的进程。 酯，暗示PKC的一个或多个亚型在预防 细胞凋亡。

Our research goal is to understand the molecular structure and function of the genes that play critical roles in malignancy, cell growth and normal differentiation. We are concentrating on a group of known oncogenes and anti-oncogenes: c-myc, abl, cbl, the bcl-2 family, the ras family and p53, p21 (waf), p107, as well as potential oncogenes: Pvt-1 and the isoforms of protein kinase C (PKC) in mouse and human tissues and tumors. We and others have shown that the deregulated expression of c-myc secondary to chromosomal translocations in the c-myc region is an essential element in the series of genetic alterations that are involved in plasmacytomagenesis in BALB/c mice and in Burkitt and AIDS-associated lymphomas in man. A "variant" subgroup of these myc-activating translocations occurs approximately 260kb 3' of c-myc in a region designated Pvt-1. We have shown that most of these variant translocations lead to the synthesis of a chimeric mRNA that includes a portion of Pvt-1 and the constant region of the kappa Ig light chain. This chimeric product may play a role in plasmacytoma development or in increasing c-myc expression. We have shown that the BALB/c mouse has an unusual defect in a special form of excision repair. The defect is only manifest in repair of DNA damage in the Pvt-1, c-myc, switch IgA and Ig kappa constant region genes, namely the sites of recurrent chromosomal translocation in mouse and human B-lymphocytic neoplasms. This form of excision repair is also unusual in that it is not coupled to RNA transcription, which is the case for most forms of DNA excision repair. We have produced a recombinant retrovirus that expresses v-abl and c- myc (ABL-MYC). This virus rapidly induces plasmacytomas in 100% of BALB/c mice. If the mice are immunized before infection with ABL-MYC, approximately 50% of the plasmacytomas produce antibodies that are directed toward the immunogen. This technology has been used to produce monoclonal antibodies to particulate, protein and peptide antigens, and it offers an alternative to hybridoma technology. This approach also works if immunized mouse B lymphocytes are infected in vitro and transplanted into syngeneic hosts. We have shown that this combination of oncogenes is unique in that it permits differentiation of B cells into plasma cells in the absence of T-cell help, in the absence of pristane priming and in the absence of helper virus. Because T cells are not necessary in the induction of plasmacytomas with this retrovirus, we are able to show that T lymphocytes actually retard the emergence of these tumors. We have cloned eight isozymes of the PKC family into expression vectors and produced cell lines that overexpress each of these isoforms in NIH3T3 fibroblasts. Immunohistochemistry has shown that each isoform translocates to different intracellular organelles when activated by phorbol esters, indicating that the substrate for each isoform is restricted to these sites. We have studied the roles of the PKC isoforms in lymphocyte growth and development. Plasmacytomas are usually IL-6-dependent in vivo and in vitro, and we have determined that withdrawal of IL-6 leads to their death by apoptosis. This process of apoptosis can be delayed by treatment with phorbol esters, implicating one or more isoforms of PKC in the prevention of apoptosis.