V-ABL TRANSFORMATION AND PRE-B CELL DIFFERENTIATION

V-ABL 转化和前 B 细胞分化

• 批准号: 2733098
• 负责人: MARY S HUANG
• 金额: $ 9.04万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-09-01 至 1999-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2733098
• 关键词: Abelson leukemia virus; B lymphocyte; cell differentiation; enzyme activity; enzyme induction /repression; gene complementation; gene rearrangement; immunoglobulin genes; leukocyte activation /transformation; molecular cloning; neoplasm /cancer genetics; northern blottings; polymerase chain reaction; protein structure function; protein tyrosine kinase; protooncogene; temperature sensitive mutant; tissue /cell culture; viral leukemogenesis; virus protein

Transformation in retroviral systems is characterized by abnormal cell growth and differentiation. Expression of the v-abl protein tyrosine kinase encoded by Abelson murine leukemia virus (Ab-MLV) induces transformation in pre-B lymphocytes. These transformed cells are arrested at the pre-B cell stage based upon their immunoglobulin (Ig) gene rearrangements and cell surface antigens. Cells transformed by a temperature sensitive (ts) mutant of Ab-MLV undergo a high frequency of Ig light chain gene rearrangement soon after inactivation of the v-abl kinase at nonpermissive temperature. In addition, up-regulated expression of at least three genes important to Ig gene rearrangement (RAG-1, RAG-2 and germline kappa gene) occurs at the nonpermissive temperature. This system provides an opportunity to study the pathways mediating differentiation arrest as a component of retroviral transformation. The goals of this study are: (1) To identify functional domains of v-abl protein which mediate differentiation arrest and the pathways used to transmit these signals. A series of abl mutants and protein tyrosine kinases will be used in genetic complementation studies to determine which functional domains mediate this process. To identify pathways by which differentiation arrest is mediated, over-expression of c-ras, c-raf and c-myc will be tested, as will dominant negative forms of these genes. Proteins to be tested will be co-expressed with ts v-abl in a single pre-B cell; the differentiation phenotype of these cells will then be assessed after inactivation of the ts v-abl kinase. (2) To determine what genes are up-regulated upon release from differentiation arrest. The v-abl protein appears to block light chain rearrangement by suppressing expression of genes important for this process. The increased expression of RAG-1, RAG-2, and germline kappa gene in ts transformants at nonpermissive temperature supports this idea. These events are necessary, but probably not sufficient, to initiate rearrangement. The differential display technique will be used to identify other genes with altered expression prior to Ig rearrangement. Combining efforts to investigate both mechanisms of regulation and their targets may contribute to a better understanding of normal pre-B cell differentiation and how disruption of this process contributes to the transformed phenotype. This may provide clues to therapeutic strategies for human diseases of abnormal B lymphocyte maturation, including immunodeficiencies and both abl and non-abl related lymphoid malignancies.

逆转录病毒系统中的转化以异常细胞为特征 生长与分化。 V-ABL蛋白酪氨酸的表达 由阿伯森鼠白血病病毒（AB-MLV）编码的激酶诱导 前B淋巴细胞中的转化。 这些转化的细胞是 根据其免疫球蛋白（IG）在前B细胞阶段被捕 基因重排和细胞表面抗原。 细胞由 AB-MLV的温度敏感（TS）突变体经历高频 V-ABL失活后不久，IG轻链基因重排 在非疗法温度下的激酶。 另外，上调 至少三个对IG基因重排重要的基因的表达 （RAG-1，RAG-2和种系Kappa基因）发生在非验证 温度。 该系统提供了研究途径的机会 介导分化逮捕作为逆转录病毒的组成部分 转型。 这项研究的目标是：（1）确定功能 V-ABL蛋白的域，介导分化停滞和 用于传输这些信号的途径。 一系列ABL突变体和 蛋白质酪氨酸激酶将用于遗传互补研究 确定哪些功能域介导此过程。 识别 介导分化停滞的途径，过表达 C-RAS，C-RAF和C-MYC将被测试，主要负面形式将进行测试 这些基因。 要测试的蛋白质将与TS V-ABL共表达 在单个前B细胞中；这些细胞的分化表型将 然后在灭活TS V-ABL激酶后进行评估。 （2）至 确定从分化释放后上调了哪些基因 逮捕。 V-ABL蛋白似乎通过 抑制基因表达对此过程很重要。 这 TS中RAG-1，RAG-2和种系Kappa基因的表达增加 在非耐药温度下的转化体支持了这一想法。 这些 事件是必要的，但可能不足以启动 重排。 差分显示技术将用于 在IG重排之前识别其他表达改变的基因。 结合调查调节机制及其两种机制的努力 目标可能有助于更好地理解正常的前B细胞 差异化以及该过程的破坏如何有助于 转化的表型。 这可能为治疗策略提供线索 对于异常B淋巴细胞成熟的人类疾病，包括 免疫缺陷以及ABL和非ABL相关淋巴机 恶性肿瘤。