REGULATION OF SQUAMOUS CELL DIFFERENTIATION

鳞状细胞分化的调节

• 批准号: 2574333
• 负责人: A M JETTEN
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ENVIRONMENTAL HEALTH SCIENCES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/2574333
• 关键词: DNA binding protein; DNA footprinting; biological signal transduction; cell cycle proteins; cell differentiation; cell growth regulation; cyclins; enzyme activity; enzyme inhibitors; gel mobility shift assay; gene deletion mutation; genetic transcription; guanine nucleotide binding protein; human tissue; interferon gamma; keratin; molecular cloning; phosphorylation; protein glutamine gamma glutamyltransferase; regulatory gene; relaxin; retinoblastoma protein; retinoids; skin; tissue /cell culture

Squamous differentiation is a multi-stage process. Irreversible growth arrest occurs early during this process of differentiation and is induced when cultured cells reached confluence or after treatment with interferon gamma (IFNg) or phorbol esters. We have been using IFNg as a tool to obtain insight in the molecular mechanisms that link the control of irreversible growth arrest with differentiation. We have shown that IFNg blocks progression of the cells through the cell cycle at a specific point in the G1 phase. The expression of several cell cycle regulatory genes was found to be down-regulated by IFNg, including cyclin A, PCNA, cdc2, p53, p21 and c-Myc synthesis. In addition, IFNg inhibits the hyperphosphorylation of the retinoblastoma protein RB. The latter was shown to be related to he inhibition of cyclin/cdk kinase activities and the up-regulation of certain cdk-inhibitors. carcinoma cells are resistant to terminal differentiation and changes in growth-regulatory genes was not observed. Irreversible growth arrest is followed by a cascade of changes in squamous cell-specific genes. Our laboratory has identified and cloned several genes that are differentially regulated during squamous differentiation, these include transglutaminase type I (TGase I), cornifin a and b, relaxin and a membrane protein related to PMP22. To study the regulation of these genes, we cloned the 5'-flanking region. Footprinting, deletion mutation and mobility shift assays were used to identify DNA elements important in the transcriptional control of these genes. AP-1-like sites were found to be involved in the transcriptional regulation of these genes and are further characterized. Retinoids are important regulators of squamous differentiation. Retinoids inhibit the expression of keratin 13, TGase I and cornifin a and b, while they induce other genes, such as keratin 19 and TGase II. Nuclear retinoid receptor-selective agonists, an antagonist and a dominant-negative RARa receptor were used to study the retinoid signaling pathways involved in these actions of retinoids. Our results have demonstrated that these genes are controlled by different retinoid signaling pathways. The induction of TGase II was shown to be mediated by an RARa-dependent mechanism.

鳞状细胞分化是一个多阶段的过程。 不可逆增长 在此分化过程的早期发生停滞， 当培养的细胞达到汇合时或用干扰素处理后， γ（IFNg）或佛波醇酯。 我们一直在使用IFNg作为工具， 获得洞察力的分子机制，连接控制 不可逆生长停滞和分化。 我们已经证明，IFNg 在特定的时间点阻断细胞在细胞周期中的进程， 在G1阶段。 几种细胞周期调控基因的表达 IFNg可下调细胞周期蛋白A，增殖细胞核抗原， cdc 2、p53、p21和c-Myc合成。 此外，IFNg抑制了 视网膜母细胞瘤蛋白RB的过度磷酸化。 后者是 显示与抑制细胞周期蛋白/CDK激酶活性有关， 某些CDK抑制剂的上调。 癌细胞是 对终末分化和生长调节变化的抗性 没有观察到基因。 不可逆的生长停滞之后是 鳞状细胞特异性基因的级联变化。 本实验室 鉴定并克隆了几个基因， 在鳞状细胞分化过程中，包括I型转氨酶 （TGase I）、角蛋白a和B、松弛素和与 PMP22。 为了研究这些基因的调控，我们克隆了5 '-侧翼序列， 地区足迹法、缺失突变和迁移率改变分析是 用于鉴定转录控制中重要的DNA元件 这些基因。AP-1样位点被发现参与了 这些基因的转录调控，并进一步表征。 类维生素A是鳞状细胞分化的重要调节因子。 维甲酸抑制角蛋白13、TGase I和角蛋白a的表达 和B，而它们诱导其他基因，如角蛋白19和TGase II。 核类视色素受体选择性激动剂、拮抗剂和药物组合物 显性负性RAR α受体用于研究维甲酸信号转导 参与维甲酸这些作用的途径。 我们的结果 表明这些基因由不同的维甲酸控制， 信号通路 TGase II的诱导被证明是由 一种RARa依赖性机制。