Ramirez F, Gambino R, Maniatis G M, Rifkind R A, Marks P A, Bank A
J Biol Chem. 1975 Aug 10;250(15):6054-8.
Previous studies have shown that mouse fetal erythroid precursor cells isolated by an immunological technique synthesize little or no globin and contain little, if any, globin mRNA, as assayed in a cell-free system (translatable mRNA). After culture for 10 hours in the presence of erythropoietin, there is a marked increase in globin synthesis and in translatable globin mRNA. The present studies were designed to measure directly the content of globin mRNA sequences during erythroid cell differentiation, by molecular hybridization with 3H-labeled DNA complementary to globin mRNA. The results indicate that few, if any, globin mRNA sequences are present in the total RNA of erythroid precursor cells. There is little or no pool of untranslated globin mRNA in these cells. After 10 hours of culture with erythropoietin, there is an increase in globin mRNA content, as ;easured by a change in the Cot1/2 values obtained by cDNA: mRNA hybridization with (Co) representing the concentration of RNA. Between 0 and 22 hours of culture, there is a 250-fold rise, and between 22 and 44 hours, a further 2-fold increase in globin mRNA content. During the 44 hours in culture, the number of cells in culture increases 2- to 3-fold. The number of globin mRNA molecules rises in erythroid precursor cells to an average value of 1800 molecules/cell during 22 hours of culture. In cultures without added erythropoietin, the absolute number of cells decreases, however, cells presumably induced to differentiate by exposure to erythropoietin in vivo continue to differentiate in vitro, accumulating globin mRNA and initiating globin synthesis.
先前的研究表明，通过免疫技术分离的小鼠胎儿红细胞前体细胞合成的珠蛋白很少或根本不合成，并且含有很少（如果有的话）的珠蛋白mRNA，这在无细胞系统（可翻译的mRNA）中得到检测。在促红细胞生成素存在下培养10小时后，珠蛋白合成和可翻译的珠蛋白mRNA显著增加。本研究旨在通过与3H标记的与珠蛋白mRNA互补的DNA进行分子杂交，直接测量红细胞系细胞分化过程中珠蛋白mRNA序列的含量。结果表明，红细胞前体细胞的总RNA中几乎不存在（如果有的话）珠蛋白mRNA序列。这些细胞中几乎没有未翻译的珠蛋白mRNA池。在用促红细胞生成素培养10小时后，珠蛋白mRNA含量增加，这是通过cDNA:mRNA杂交获得的Cot1/2值的变化来衡量的，其中（Co）代表RNA的浓度。在培养的0至22小时之间，珠蛋白mRNA含量增加了250倍，在22至44小时之间，又进一步增加了2倍。在培养的44小时内，培养的细胞数量增加了2至3倍。在培养22小时期间，红细胞前体细胞中珠蛋白mRNA分子的数量增加到平均每细胞1800个分子。在未添加促红细胞生成素的培养物中，细胞的绝对数量减少，然而，可能在体内暴露于促红细胞生成素而被诱导分化的细胞在体外继续分化，积累珠蛋白mRNA并开始合成珠蛋白。
