V-ABL TRANSFORMATION AND PREB CELL DIFFERENTIATION

V-ABL 转化和 PREB 细胞分化

基本信息

批准号：
2106721
负责人：
MARY S HUANG
金额：
$ 1.13万
依托单位：
DANA-FARBER CANCER INST
依托单位国家：
美国
项目类别：
财政年份：
1994
资助国家：
美国
起止时间：
1994-09-01 至 1995-08-31
项目状态：
已结题

项目摘要

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.

逆转录病毒系统转化的特点是细胞异常生长和分化。 v-abl 蛋白酪氨酸的表达由阿贝尔森鼠白血病病毒 (Ab-MLV) 编码的激酶前B淋巴细胞的转化。这些转化的细胞是根据免疫球蛋白 (Ig)，将其捕获在前 B 细胞阶段基因重排和细胞表面抗原。细胞转化为 Ab-MLV 的温度敏感 (ts) 突变体经历高频率 v-abl 失活后不久 Ig 轻链基因重排激酶在不允许的温度下。此外，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）发生在非许可性温度。该系统提供了研究途径的机会作为逆转录病毒的一个组成部分介导分化停滞转变。本研究的目的是：（1）确定功能介导分化停滞的 v-abl 蛋白结构域和用于传输这些信号的路径。一系列 abl 突变体和蛋白酪氨酸激酶将用于遗传互补研究以确定哪些功能域介导此过程。识别介导分化停滞的途径，过度表达将测试 c-ras、c-raf 和 c-myc，以及显性阴性形式这些基因。待测蛋白将与 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 ts v-abl 激酶失活后进行评估。 (2) 至确定哪些基因在分化释放后上调逮捕。 v-abl 蛋白似乎可以通过以下方式阻断轻链重排：抑制对此过程重要的基因的表达。这 ts 中 RAG-1、RAG-2 和种系 kappa 基因的表达增加在不允许的温度下的转化体支持了这个想法。这些事件是必要的，但可能不足以启动重新排列。差分显示技术将用于在 Ig 重排之前识别表达改变的其他基因。结合努力研究监管机制及其影响靶标可能有助于更好地了解正常前 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用于 B 淋巴细胞成熟异常的人类疾病，包括免疫缺陷以及 abl 和非 abl 相关淋巴恶性肿瘤。