CELL CYCLE GENES AND CELLULAR SENESCENCE AND AGING

细胞周期基因与细胞衰老

• 批准号: 2052301
• 负责人: STEPHEN J ELLEDGE
• 金额: $ 13.35万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-01-01 至 1996-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2052301
• 关键词: DNA replication; aging; antisense nucleic acid; cell age; cell cycle; cyclins; embryo /fetus tissue /cell culture; fibroblasts; gene expression; human tissue; laboratory rabbit; messenger RNA; microinjections; mutant; phosphorylation; protein kinase; regulatory gene; site directed mutagenesis; yeasts

Normal human cells in culture show a limited division potential known as senescence. Cells divide for a defined number of generations and then fail to enter subsequent S phases. Available evidence suggests that senescent cells have intact a pathway that prevents some aspect of activation of the cell cycle regulatory apparatus. Our overall interests are to determine what aspect of activation is absent, and whether introduction of cell cycle regulatory genes and proteins that normally promote entry into S phase can overcome this inactivation. Recent genetic and biochemical evidence suggests that the G1 to S phase transition in the eukaryotic cell cycle is controlled, in part, by the coordinate action of a protein kinase(s), p34cdc2, and its associated regulatory subunits, cyclins. The principal focus of this program will be the analysis of the role that Cdk2 and Cdc2Hs protein kinases and G1 cyclins play in the process of senescence and the regulation of cell cycle transitions. Cdk2 is a Cdc2-related protein kinase that forms a distinct sub-family of Cdc2 kinases. It is currently believed that Cdk2, which is found complexed with cyclin A, is involved in the control of DNA replication and/or the G1-S transition. Depletion of the Xenopus Cdk2 protein, but not the Cdc2 protein, blocks DNA replication in cycling embryonic extracts in vitro. Further evidence suggestive of an early role in the cell cycle is that some CDK2 mRNA persists in G0 cells and, when G0 cells are stimulated to enter the cell cycle, its mRNA levels increase in G1 prior to the increase in CDC2Hs mRNAs. The specific aims of this research are to use the G1 cyclins, CDK2 and CDC2Hs genes as tools to: 1) explore the expression state of quiescent and senescent cells with respect to key cell cycle regulators, 2) determine the effects of removal of Cdk2 and other relevant proteins on the progression of the cell cycle, 3) to explore regulation of Cdk2 by phosphorylation, and 4) to determine if expression of combinations of cyclins and p34 protein kinases can promote entry of quiescent or senescent cells into S phase. Our analysis of G1 control in senescent cells is aimed at identifying those key regulators whose functions are negatively regulated in aging cells. This information can be used to further elaborate the mechanisms by which negative regulation is established in senescent cells.

培养中的正常人类细胞表现出有限的分裂潜力，称为 衰老。 细胞分裂一定数量的代数，然后 无法进入后续S期。 现有证据表明 衰老细胞具有完整的通路，可防止某些方面的衰老 细胞周期调节装置的激活。 我们的整体利益 是为了确定激活的哪个方面缺失，以及是否 引入通常情况下的细胞周期调节基因和蛋白质 促进进入S期可以克服这种失活。 最近的 遗传和生化证据表明 G1 到 S 期 真核细胞周期的转变部分由 蛋白激酶 p34cdc2 及其相关蛋白激酶的协调作用 调节亚基，细胞周期蛋白。 该计划的主要重点将是 分析Cdk2和Cdc2Hs蛋白激酶与G1的作用 细胞周期蛋白在衰老过程和细胞调控中发挥作用 循环转换。 Cdk2 是一种 Cdc2 相关蛋白激酶，形成 Cdc2 激酶的独特亚家族。 目前认为Cdk2， 被发现与细胞周期蛋白 A 复合，参与 DNA 的控制 复制和/或 G1-S 转变。 非洲爪蟾 Cdk2 的耗尽 蛋白质，但不是 Cdc2 蛋白质，在循环中阻止 DNA 复制 体外胚胎提取物。 进一步的证据表明早期 在细胞周期中的作用是一些 CDK2 mRNA 持续存在于 G0 细胞中，并且， 当G0细胞被刺激进入细胞周期时，其mRNA水平 G1 的增加先于 CDC2Hs mRNA 的增加。 本研究的具体目的是使用 G1 细胞周期蛋白、CDK2 和 CDC2Hs 基因作为工具：1) 探索静止期的表达状态 和衰老细胞与关键细胞周期调节因子相关，2) 确定去除 Cdk2 和其他相关蛋白对 细胞周期的进展，3) 探索 Cdk2 的调节 磷酸化，以及4)确定是否表达组合 细胞周期蛋白和 p34 蛋白激酶可以促进静止或 衰老细胞进入S期。 我们对衰老 G1 控制的分析 细胞的目的是识别那些关键的调节因子，其功能是 在衰老细胞中受到负调控。 该信息可用于 进一步细化负面监管的机制 在衰老细胞中建立。