E2F AND APOPTOSIS

E2F 和细胞凋亡

基本信息

批准号：
6628465
负责人：
TIMOTHY F KOWALIK
金额：
$ 28.7万
依托单位：
UNIV OF MASSACHUSETTS MED SCH WORCESTER
依托单位国家：
美国
项目类别：
财政年份：
2000
资助国家：
美国
起止时间：
2000-02-05 至 2005-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/6628465
关键词：
apoptosis brca gene cell proliferation cyclin dependent kinase enzyme activity gene induction /repression gene mutation nucleic acid sequence oligonucleotides oncoprotein p21 p53 gene /protein tissue /cell culture transcription factor

项目摘要

The long-term objectives of the proposed research are to define the molecular mechanisms underlying the normal relationship between proliferation and apoptosis and to understand the consequences of uncoupling this connection in diseases like cancer. Mounting evidence points to central roles of the Rb/E2F pathway in the commitment of cells to S phase and for p53 to limit the proliferative capacity of this pathway by inducing growth arrest or apoptosis. In support of this relationship, we have previously shown that expression of E2F1 not only leads to S phase induction, but also to a p53-dependent apoptosis. This apoptosis is specific to E2F1 and coincides with an E2F1-mediated accumulation of p53 protein. Both of these processes appear to be stimulated by E2F1 transcriptional activity. Using recombinant adenoviruses to efficiently express cDNAs in mouse embryo fibroblasts (MEFs) that are nullizygous for p19ARF, p53 or double null for Mdm2/p53, we now have evidence to suggest that E2F1 signals apoptosis and p53 accumulation through separate pathways. It has been suggested that E2F1 induces p53 accumulation and apoptosis by activating the p19ARF pathway. However, we find that although p19ARF is downstream of E2F1 in signaling p53 accumulation, p19ARF is not necessary for E2F1- mediated apoptosis. Interestingly, we do find that Mdm2 is required for both E2F1-mediated p53 accumulation and apoptosis. This implies that the p53 accumulation and apoptosis pathways diverge at the point where Mdm2 affects p53 function. To further investigate the different pathways by which E2F1 induces p53 accumulation and apoptosis, I plan to 1) characterize the pathway by which E2F expression leads to p53 protein accumulation and analyze the consequences of inducing this pathway; 2) determine the steps involved in a p19ARF-independent pathway that leads to p53-dependent apoptosis; and 3) identify apoptosis genes that are specifically induced by E2F1.

拟议研究的长期目标是确定增殖和凋亡之间正常关系的分子机制，并了解在癌症等疾病中解开这种联系的后果。越来越多的证据表明，Rb/E2F 通路在细胞进入 S 期过程中发挥着核心作用，p53 通过诱导生长停滞或凋亡来限制该通路的增殖能力。为了支持这种关系，我们之前已经证明 E2F1 的表达不仅导致 S 期诱导，而且还导致 p53 依赖性细胞凋亡。这种细胞凋亡是 E2F1 特异性的，并且与 E2F1 介导的 p53 蛋白积累一致。这两个过程似乎都受到 E2F1 转录活性的刺激。使用重组腺病毒在 p19ARF、p53 无效或 Mdm2/p53 双无效的小鼠胚胎成纤维细胞 (MEF) 中高效表达 cDNA，我们现在有证据表明 E2F1 通过不同的途径发出细胞凋亡和 p53 积累的信号。有人认为E2F1通过激活p19ARF途径诱导p53积累和细胞凋亡。然而，我们发现虽然p19ARF在p53积累信号中是E2F1的下游，但p19ARF对于E2F1介导的细胞凋亡不是必需的。有趣的是，我们确实发现 Mdm2 对于 E2F1 介导的 p53 积累和细胞凋亡都是必需的。这意味着 p53 积累和凋亡途径在 Mdm2 影响 p53 功能的点上出现分歧。为了进一步研究E2F1诱导p53积累和凋亡的不同途径，我计划1）表征E2F表达导致p53蛋白积累的途径并分析诱导该途径的后果； 2) 确定导致 p53 依赖性细胞凋亡的 p19ARF 独立途径所涉及的步骤； 3) 鉴定E2F1特异性诱导的凋亡基因。