de Wet W J, Chu M L, Prockop D J
J Biol Chem. 1983 Dec 10;258(23):14385-9.
Homologous DNA fragments were prepared from cloned cDNAs for the pro-alpha 1(I) and pro-alpha 2(I) chains of human type I procollagen. The DNA fragments were then used to develop a dot blot hybridization assay for mRNAs for pro-alpha 1(I) and pro-alpha 2(I) chains in skin fibroblasts. In normal fibroblasts, the ratio of the steady state levels of the two mRNAs was 1.94 +/- 0.34 S.D. The ratio for the rates of synthesis of the two pro-alpha chains in the same cells was 1.84 +/- 0.13 S.D. Since the two ratios were essentially the same, the results indicated that the mRNAs for the two chains are translated at about the same rates. Therefore, there is no need to invoke translational control or more complex mechanisms to explain synthesis of pro-alpha 1(I) and pro-alpha 2(I) chains in a stoichiometry of 2:1. The dot blot hybridization assay was also used to examine the levels of the mRNAs in fibroblasts from several variants of osteogenesis imperfecta. In two of the variants, the ratios of the steady state levels of mRNAs for pro-alpha 1(I) and pro-alpha 2(I) chains were 3.05 and 2.52, respectively. In the same fibroblasts, the ratios for the rates of synthesis of the two chains were 2.99 +/- 0.43 and 2.45 +/- 0.16, respectively. Therefore, even though the ratios of the levels of the two mRNAs in the fibroblasts were abnormal, the two mRNAs were still translated at the same rates, and there was no evidence of differential regulation at the translational level.
从人I型前胶原的前α1（I）链和前α2（I）链的克隆cDNA中制备同源DNA片段。然后将这些DNA片段用于开发一种斑点印迹杂交分析方法，以检测皮肤成纤维细胞中前α1（I）链和前α2（I）链的mRNA。在正常成纤维细胞中，两种mRNA稳态水平的比值为1.94±0.34标准差。同一细胞中两条前α链合成速率的比值为1.84±0.13标准差。由于这两个比值基本相同，结果表明两条链的mRNA翻译速率大致相同。因此，无需引入翻译控制或更复杂的机制来解释前α1（I）链和前α2（I）链以2:1化学计量比的合成。斑点印迹杂交分析方法还用于检测几种成骨不全变体的成纤维细胞中mRNA的水平。在其中两个变体中，前α1（I）链和前α2（I）链mRNA稳态水平的比值分别为3.05和2.52。在相同的成纤维细胞中，两条链合成速率的比值分别为2.99±0.43和2.45±0.16。因此，尽管成纤维细胞中两种mRNA水平的比值异常，但两种mRNA的翻译速率仍然相同，并且没有证据表明在翻译水平存在差异调节。
