Avvedimento V E, Monticelli A, Tramontano D, Polistina C, Nitsch L, Di Lauro R
Eur J Biochem. 1985 Jun 18;149(3):467-72. doi: 10.1111/j.1432-1033.1985.tb08948.x.
We have measured the synthesis of thyroglobulin in two differentiated cell lines, FRTL-5 and FRTL-424, and two transformed thyroid cell lines, FRA and 1-5G. The untransformed cells actively synthesized and exported thyroglobulin in the medium: however, the FRTL-5 cell line synthesized seven times less thyroglobulin than the FRTL-424 cell line, even though both cell types contained equal amounts of functional thyroglobulin mRNA. In contrast the transformed cells expressed extremely low levels of thyroglobulin mRNA, even though there was no detectable change in gene structure or copy number as determined by Southern blot analysis. On the basis of these data we conclude that (a) the different levels of thyroglobulin synthesis in the two untransformed cell lines are due to stable post-transcriptional alterations in the biosynthesis of thyroglobulin and (b) the transformation of thyroid cells results in a substantial reduction in thyroglobulin gene expression.
我们已经在两种分化的细胞系FRTL - 5和FRTL - 424，以及两种转化的甲状腺细胞系FRA和1 - 5G中测量了甲状腺球蛋白的合成。未转化的细胞在培养基中积极合成并分泌甲状腺球蛋白：然而，FRTL - 5细胞系合成的甲状腺球蛋白比FRTL - 424细胞系少7倍，尽管两种细胞类型含有等量的功能性甲状腺球蛋白mRNA。相比之下，转化细胞表达的甲状腺球蛋白mRNA水平极低，尽管通过Southern印迹分析确定基因结构或拷贝数没有可检测到的变化。基于这些数据，我们得出结论：(a)两种未转化细胞系中甲状腺球蛋白合成水平的差异是由于甲状腺球蛋白生物合成过程中稳定的转录后改变；(b)甲状腺细胞的转化导致甲状腺球蛋白基因表达大幅降低。
