REGULATION OF DIFFERENTIATION IN LUNG AND EPIDERMAL KERATINOCYTES

工作总结：鳞状细胞分化是一种 发生在许多组织中的多阶段过程。分子链接 在控制生长停滞和分化之间 学习。深入了解这些机制不仅对 了解正常分化的控制，也了解 鳞状化生和癌症等疾病的缺陷。几个 不同的信号通路可诱导鳞状细胞分化 包括由干扰素伽马和佛波酯引发的药物。 我们证明角质形成细胞的生长受阻于 位于细胞周期G1期的特定时间点，并伴随着 抑制Rb磷酸化，降低CDK活性和 Cdk抑制因子p27、p21和p16的诱导。尽管异国情结 P21或p27的表达导致生长停滞，而细胞不会 区分表明其他信号参与了 末端分化。癌细胞对终末期耐药 生长调节基因和基因的分化和变化 没有观察到鳞状细胞特异基因的诱导。我们有 鉴定和克隆了几个受调控的基因 鳞状分化，包括转谷氨酰胺酶I型(TGase) I)和一种膜蛋白CL-20/EMP-1。为了研究 这些基因的转录调控，我们克隆了上游 TGase I和CL20的调节区，并由 足迹、缺失突变和迁移率改变分析DNA 与CREB/AP-1类似的站点在其 转录控制。2.9kb的上游监管区域 TGase I基因调控氯霉素的表达 体内分析了乙酰基转移酶(CAT)报告基因。 这些研究表明，-2.9kb启动子区域包含所有 针对特定问题和差异化的适当信息 TGase I的表达。

Summary of Work: Squamous differentiation is a multi-stage process that occurs in many tissues. The molecular link between control of growth arrest and differentiation is being studied. Insight into these mechanisms are important not only for understanding the control of normal differentiation but also the defects in diseases such as squamous metaplasia and cancer. Several different signaling pathways can induce squamous differentiation including those initiated by interferon gamma and phorbol esters. We demonstrated that keratinocytes become growth arrested at a specific point in the G1 of the cell cycle and is accompanied by an inhibition of Rb phosphorylation, decrease in cdk activity and induction of the cdk-inhibitors p27, p21 and p16. Although ectopic expression of p21 or p27 causes growth arrest, cells do not differentiate suggesting that additional signals are involved in terminal differentiation. Carcinoma cells are resistant to terminal differentia- tion and changes in growth-regulatory genes and induction of squamous- specific genes were not observed. We have identified and cloned several genes that are regulated during squamous differentiation, including transglutaminase type I (TGase I) and a membrane protein CL-20/EMP-1. To study the transcriptional regulation of these genes, we cloned the upstream regulatory region of TGase I and CL20, and determined by footprinting, deletion mutation and mobility shift assays DNA elements that CREB/AP-1-like sites are important in their transcriptional control. The 2.9kb upstream regulatory region of the TGase I gene to control the expression of a chloramphenicol acetyltransferase (CAT) reporter gene was also analyzed in vivo. These studies showed that the -2.9 kb promoter region contains all the information for the proper issue- and differentiation-specific expression of TGase I.