Helaakoski T, Pajunen L, Kivirikko K I, Pihlajaniemi T
Department of Medical Biochemistry, University of Oulu, Finland.
J Biol Chem. 1990 Jul 15;265(20):11413-6.
Mouse F9 teratocarcinoma stem cells differentiate in monolayer cultures in the presence of retinoic acid, dibutyryl cAMP, and isobutyl methylxanthine. This differentiation is associated with a marked increase in the synthesis rates and mRNA concentrations of basement membrane proteins such as type IV collagen. We report here that the differentiation also involves an increase of up to 50-fold in the concentrations of the mRNAs for the alpha and beta subunits of prolyl 4-hydroxylase, the enzyme required for the cotranslational and post-translational hydroxylation of proline residues in collagens. The time courses and magnitudes of increases in these two mRNA concentrations were similar to those observed in the same experiments for the mRNA of the alpha chain of type IV collagen. In the differentiated F9 cells the concentration of the alpha subunit mRNA was about 30% of the beta subunit mRNA concentration. Northern blot analyses indicated that the sizes of the alpha and beta subunit mRNAs in the differentiated mouse F9 cells are similar to those in human skin fibroblasts. The F9 cell differentiation system appears to provide a useful model for studies on the regulation of prolyl 4-hydroxylase synthesis.
在视黄酸、二丁酰环磷腺苷和异丁基甲基黄嘌呤存在的情况下，小鼠F9畸胎瘤干细胞在单层培养中发生分化。这种分化与基底膜蛋白（如IV型胶原）的合成速率和mRNA浓度显著增加有关。我们在此报告，这种分化还涉及脯氨酰4-羟化酶α和β亚基的mRNA浓度增加高达50倍，脯氨酰4-羟化酶是胶原蛋白中脯氨酸残基共翻译和翻译后羟化所需的酶。这两种mRNA浓度增加的时间进程和幅度与在相同实验中观察到的IV型胶原α链mRNA的时间进程和幅度相似。在分化的F9细胞中，α亚基mRNA的浓度约为β亚基mRNA浓度的30%。Northern印迹分析表明，分化的小鼠F9细胞中α和β亚基mRNA的大小与人类皮肤成纤维细胞中的相似。F9细胞分化系统似乎为研究脯氨酰4-羟化酶合成的调控提供了一个有用的模型。
