REGULATION OF DIFFERENTIATION OF TRACHEOBRONCHIAL EPITHELIAL CELLS

气管支气管上皮细胞分化的调控

• 批准号: 3777498
• 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/3777498
• 关键词: cell differentiation; crosslink; enzyme induction /repression; enzyme substrate; gene expression; genetic promoter element; genetic regulation; genetic transcription; immunocytochemistry; in situ hybridization; molecular cloning; nucleic acid repetitive sequence; nucleic acid sequence; posttranscriptional RNA processing; protein glutamine gamma glutamyltransferase; reporter genes; respiratory epithelium; retinoid binding proteins; retinoids; tissue /cell culture; transfection

The focus of the research in the Cell Biology Section is to understand the molecular mechanisms that regulate the differentiation of tracheobronchial and epidermal epithelial cells and in particular the role that retinoids play in this process. Retinoids affect a specific stage in the multi-stage process of squamous differentiation. These agents do not block the commitment to irreversible growth arrest but specifically suppress the induction of squamous cell-specific genes. The formation of the crosslinked envelope, a layer of crosslinked protein deposited beneath the plasma membrane, is a characteristic feature of squamous differentiation. The promoter of the transglutaminase type I gene, the enzyme that catalyzes the protein crosslinking, has been cloned and sequenced. Different regions of the promoter of this gene were cloned into reporter gene constructs and transfected into cells in order to analyze what elements are important in the transcriptional control of this gene. Putative AP1 and AP2 sites were found to be important in the transcriptional control of this gene. The cDNA clone SQ37 was characterized and found to encode a new squamous cell- specific protein named cornifin. Immunohistochemistry and in situ hybridization localized the cornifin protein and mRNA in the suprabasal layers of several squamous differentiating tissues. Cornifin is a cytosolic protein that contains 13 repeats of an octapeptide (consensus sequence, EPCQPKVP) at the carboxy terminus and is high in the content of proline and glutamine. Cornfin is an excellent substrate for transglutaminase type I and appears to function as a precursor protein for the crosslinked envelope. Cornifin appears to be a gene family since other genes were cloned exhibiting high homology to cornifin. The suppression of transglutaminase type I by retinoic acid occurs at the transcriptional level and appears to be mediated through nuclear retinoic acid receptors. The suppression of cornifin expression by retinoic acid appears to occur at least in part at a post-transcriptional level. Retinoids selective for specific retinoid receptors are being used to determine which receptor is mediating the various effects of retinoids.

细胞生物学部分的研究重点是了解 调节气管支气管分化的分子机制 和表皮上皮细胞，特别是类维生素A的作用 在这个过程中发挥。 类维生素A影响多阶段中的特定阶段 鳞状细胞分化的过程。 这些代理不会阻止 致力于不可逆转的增长停滞，但具体抑制 鳞状细胞特异性基因的诱导。 的形成 交联包膜，沉积在膜下方的一层交联蛋白质 质膜，是鳞状分化的特征。 I型转谷氨酰胺酶基因的启动子，该酶催化 蛋白质交联已被克隆并测序。 不同地区 该基因的启动子被克隆到报告基因构建体中并且 转染到细胞中以分析哪些元素在 该基因的转录控制。 假定的 AP1 和 AP2 站点是 发现对该基因的转录控制很重要。 这 cDNA 克隆 ​​SQ37 被表征并被发现编码一种新的鳞状细胞- 称为cornifin的特殊蛋白质。 免疫组织化学和原位 杂交将 Cornifin 蛋白和 mRNA 定位于基底上层 数层鳞状分化组织。 康尼芬是一种 含有 13 个八肽重复的胞浆蛋白（共识 序列，EPCQPKVP）位于羧基末端，并且含量高 脯氨酸和谷氨酰胺。 Cornfin 是优良的基材 I 型转谷氨酰胺酶，似乎充当以下物质的前体蛋白： 交联的信封。 Cornifin 似乎是自其他基因家族以来的一个基因家族 克隆的基因与 Cornifin 表现出高度同源性。 压制 视黄酸引起的 I 型转谷氨酰胺酶发生在转录 水平，似乎是通过核视黄酸受体介导的。 视黄酸对 Cornifin 表达的抑制似乎发生在 至少部分是在转录后水平。 类维生素A选择性 特定的类维生素A受体被用来确定哪个受体是 介导类维生素A的各种作用。