MECHANISM OF TRANSFORMATION BY THE V-MYB ONCOGENE

本提案的总体目标是了解该机制 禽白血病原癌基因v-myb致骨髓性白血病 成髓细胞瘤病毒（AMV）。 这种致癌基因只会导致 造血系统恶性肿瘤及其蛋白产物是一种 一小群核癌基因产物。 一系列的好- 将使用定义的突变引入v-myb 重组DNA技术。 这些变异的v-myb基因 然后将其引入感染性的、可独立选择的新- myb前病毒。 这些前病毒可以在大肠杆菌中瞬时表达。 猴COS细胞，并在克隆的QT 6鹌鹑中连续表达 成纤维细胞和BM-2鸡成纤维细胞。 相关性 通过这些突变病毒进行体外和体内转化， 其突变型p48 v- myb癌基因产品将用于解决具体问题： 1. v-myb所需的最小区域是多少 转化？ 2. p48 v核转运的信号序列是什么- myb，以及这种转运是白血病发生所必需的吗？ 3. p48 v-myb的体外DNA结合活性是否与p48 v-myb 转化能力？ 4. p48 v-myb在体内有哪些特异性的分子间联系 是转化所必需的吗 5. p48 v-myb是否调节c-myb的表达， 一般在V-myb转化细胞中不表达？ 6. p48 v-myb是一种通用的转录激活因子吗？ 据报道，腺病毒E1 A、c-myc和 HTLV-I和II X基因。 7. p48 v-myb是否是DNA完整复制所必需的？ 细胞和分离的细胞核中的AMV转化细胞？ 这些关于v-myb的研究似乎与 因为c-myb原癌基因是 在人类白血病中高水平表达，其表达是 在髓样分化过程中下调，在 某些人类白血病细胞系及其染色体定位 这表明它可能参与特定的易位， 人类白血病 此外，c-myb被逆转录病毒激活， 插入是一系列小鼠造血肿瘤。

The overall goal of this proposal is to understand the mechanism of myeliod leukemogenesis by v-myb, the oncogene of avian myeloblastosis virus (AMV). This oncogene causes only hematopoietic malignancies and its protein product is one of a small group of nuclear oncogene products. A series of well- defined mutations will be introduced into v-myb using recombinant DNA technology. These mutated v-myb genes will then be introduced into infectious, independently selectable neo- myb proviruses. These proviruses can be transiently expressed in simian COS cells and continuously expressed in cloned QT6 quail fibroblasts and in BM-2 chicken myeblostasts. Correlation of transformation in vitro and in vivo by these mutant viruses with the structural and functional properties of their mutant p48 v- myb oncogene products will be used to address specific questions: 1. What is the minimum region of v-myb required for transformation? 2. What is the signal sequence for nuclear transport of p48 v- myb, and is such transport necessary for leukemogenesis? 3. Is the in vitro DNA binding activity of p48 v-myb related to its transforming capacity? 4. What specific intermolecular associations of p48 v-myb in vivo are required for transformation? 5. Does p48 v-myb regulate the expression of c-myb, which is generally not expressed in v-myb transformed cells? 6. Is p48 v-myb a general trans-activator of transcription as has been reported for the products of adenovirus E1A, c-myc, and HTLV-I and II X genes. 7. Is p48 v-myb required for ongoing DNA replication in intact cells and in isolated nuclei of AMV-transformed cells? These studies of v-myb appear to be particularly relevant to human leukemogenesis because the c-myb proto-oncogene is expressed at high levels in human leukemias, its expression is down-regulated during myeloid differentiation, it is amplified in certain human leukemic cell lines, and its chromosomal location suggests that it may be involved in specific translocations in human leukemias. In addition, c-myb is activated by retrovial insertion is a series of murine hematopoietic tumors.