Astigiano S, Sherman M I, Abarzúa P
Department of Oncology and Virology, Roche Research Center, Nutley, NJ 07110.
Environ Health Perspect. 1989 Mar;80:25-38. doi: 10.1289/ehp.898025.
Embryonal carcinoma (EC) cells offer an interesting model system for evaluating differentiation because the cells are pluripotent, thus resembling germ cells and embryonic stem cells, and because a number of agents have been defined that are capable of promoting the differentiation of these cells. This chapter examines how EC cells might be triggered to differentiate, with emphasis on retinoic acid because this compound is a potent, naturally occurring inducer that has been studied extensively in this system. The nature of alterations in gene expression during EC cell differentiation is reviewed from the perspective of evaluating whether these changes are likely to be responsible for, or a result of, the differentiation event. Finally, we consider in molecular terms why EC cells, but not their differentiated derivatives, are refractory to the expression of many viral genomes following infection. Based upon these studies, we propose that fundamental changes in gene expression that are observed when differentiation is triggered in EC cells are likely to be due to the disappearance or neutralization of strong repressor elements.
胚胎癌（EC）细胞为评估分化提供了一个有趣的模型系统，这是因为这些细胞具有多能性，因而类似于生殖细胞和胚胎干细胞，还因为已确定了许多能够促进这些细胞分化的因子。本章探讨如何触发EC细胞进行分化，重点是视黄酸，因为这种化合物是一种强效的天然诱导剂，已在该系统中得到广泛研究。从评估这些变化是否可能是分化事件的原因或结果的角度，综述了EC细胞分化过程中基因表达改变的性质。最后，我们从分子角度思考为什么EC细胞，而不是其分化衍生物，在感染后对许多病毒基因组的表达具有抗性。基于这些研究，我们提出，当EC细胞触发分化时观察到的基因表达的根本变化可能是由于强抑制元件的消失或失活。
