STRUCTURE AND FUNCTION OF ONCOGENES AND ANTI-ONCOGENES

癌基因和抗癌基因的结构和功能

• 批准号: 2468451
• 负责人: J F MUSHINSKI
• 金额: --
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/2468451
• 关键词: B lymphocyte; Retroviridae; antibody formation; antitumor antibody; apoptosis; cell cell interaction; cell differentiation; chimeric proteins; chromosome translocation; cyclins; gene expression; helper T lymphocyte; human tissue; immunoglobulin genes; interleukin 6; laboratory mouse; molecular cloning; monoclonal antibody; neoplasm /cancer genetics; neoplastic transformation; oncogenes; plasma cell neoplasm; protein kinase C; tissue /cell culture

Our research goal is to understand the molecular structure and function of the genes that play critical roles in normal growth and differentiation, neoplastic transformation, and apoptosis in mouse and human tissues and tumors of the hematopoietic system. We study oncogenes, c-myc, v-raf and v-abl; anti-oncogenes, esp. the bcl-2 family; cell cycle-regulating proteins (cyclins) and their inhibitors, p21 (waf) and p16; as well as molecules that transduce signals within the cell, e.g., protein kinase C (PKC). 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. We have also shown that c-myc can also be dysregulated in these tumor cells by retroviral insertion of strong enhancers in myc's upstream flank. It is not known why BALB/c mice are particularly susceptible to these genetic insults, but we have a candidate mechanism. We have found that the BALB/c mouse has an unusual defect in a special form of excision repair of DNA damage. This form of excision repair is unusual in that it is not coupled to RNA transcription, which is usual for DNA excision repair. Furthermore, the defect is only manifest in repair of DNA damage in the c-myc, Pvt1, switch Ig alpha and Ig kappa genes, namely the sites of recurrent chromosomal translocation in B-lymphocytic neoplasms. This is a plausible mechanism for the production of the gene-specific, strain-specific genomic instability that predisposes to the chromosome translocations that lead to constitutive expression of c-myc. This overexpression of c-myc, in turn, leads to an extension of gene-specific genetic instability to a new subset of genes, including cyclin D2. This gene becomes amplified and overexpressed in the face of c-myc overexpression, contributing to cell proliferation. We have produced a recombinant retrovirus that expresses v-abl and c-myc (ABL-MYC). This virus rapidly induces plasmacytomas in vitro and in vivo in BALB/c, nude and other strains of mice. This technology has been used to produce monoclonal antibodies to parasites, particulate, protein and peptide antigens, and it offers an alternative to hybridoma technology. 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 and without ip pristane. Because T cells are not necessary in the induction of plasmacytomas with this retrovirus, we were able to show that normal T cells actually retard the emergence of these tumors. We have cloned eight PKC isozymes into expression vectors and produced cell lines that overexpress each of these isoforms in a variety of hematopoietic cell lines. Plasmacytomas are usually IL-6-dependent in vivo and in vitro, and withdrawal of IL-6 leads to their death by apoptosis. This process of apoptosis can be delayed by activating PKC-d with a specific phorbol ester. PKC-delta is also able to mediate macrophage differentiation in promyelocytes and cytoskeleton- mediated changes in the shape of B lymphocytes. We wished to determine which portion of the PKC-delta protein determines its isozyme-specific functions by constructing expression vectors that overexpress chimeric molecules that are half PKC-delta and half PKC-epsilon. The overexpression of these chimeras in different cell types showed that the C-terminal half, containing the catalytic domain, appears to bear most of the isoform-specific determinants of myeloid differentiation and transformation.

我们的研究目标是了解分子结构和功能 在正常生长中起关键作用的基因， 分化、肿瘤转化和凋亡， 人体组织和造血系统肿瘤。我们研究 癌基因c-myc、v-raf和v-abl;抑癌基因尤其是bcl-2 家族;细胞周期调节蛋白（细胞周期蛋白）及其抑制剂， p21（waf）和p16;以及在细胞内传递信号的分子。 所述细胞，例如，蛋白激酶C（PKC）。我们和其他人已经证明， c-myc基因表达失调继发于染色体 c-myc区的易位是一个重要的因素， 一系列与浆细胞发生有关的遗传改变 在BALB/c小鼠和Burkitt和人类艾滋病相关淋巴瘤中，我们 还表明c-myc在这些肿瘤中也可能失调， 通过逆转录病毒在myc基因上游插入强增强子， 侧翼 目前尚不清楚为什么BALB/c小鼠对这些特别敏感。 基因侮辱但我们有一个候选机制我们发现 BALB/c小鼠在一种特殊切除形式中具有不寻常的缺陷 修复DNA损伤。这种形式的切除修复是不寻常的， 它不与RNA转录偶联，RNA转录通常用于DNA切除 修复.此外，该缺陷仅表现在DNA的修复中 c-myc、Pvt 1、开关IG α和IG κ基因的损伤，即 B淋巴细胞中复发性染色体易位的位点 肿瘤。这是一个合理的机制，生产的 基因特异性，菌株特异性基因组不稳定性， 染色体易位，导致组成型表达 c-myc这种c-myc的过度表达反过来又导致了 基因特异性遗传不稳定性的一个新的基因子集，包括 细胞周期蛋白D2。这种基因在脸部被放大并过度表达 c-myc过度表达，促进细胞增殖。 我们已经生产了表达v-abl的重组逆转录病毒， c-myc（ABL-MYC）。该病毒在体外快速诱导浆细胞瘤， 在BALB/c、裸鼠和其它品系小鼠体内。该技术具有 被用于生产单克隆抗体，针对寄生虫，颗粒， 蛋白质和肽抗原，它提供了一种替代杂交瘤 技术.我们已经证明这种癌基因的组合是独特的 因为它允许B细胞分化成浆细胞， 没有T细胞帮助和没有ip降植烷。因为T细胞不是 在用这种逆转录病毒诱导浆细胞瘤中， 能够证明正常的T细胞实际上延缓了 这些肿瘤。 我们将八种PKC同工酶克隆到表达载体中， 以多种形式过表达这些同种型中的每一种的细胞系 造血细胞系。浆细胞瘤通常是IL-6依赖性的， 在体内和体外，IL-6的撤回导致他们的死亡， 凋亡通过激活PKC-d可以延缓细胞凋亡的进程 一种特殊的佛波醇酯PKC-δ还能够介导 早幼粒细胞和细胞骨架介导的巨噬细胞分化 B淋巴细胞形状的变化。我们希望确定 PKC-δ蛋白的一部分决定其同工酶特异性 通过构建过表达嵌合的 半PKC δ半PKC β的分子。的 这些嵌合体在不同细胞类型中的过表达表明， 含有催化结构域的C-末端一半似乎带有 髓样分化的大多数同种型特异性决定因素 和转变。