Kecskemethy N, Schäfer K P
Eur J Biochem. 1982 Sep 1;126(3):573-82. doi: 10.1111/j.1432-1033.1982.tb06819.x.
The differentiation of T-cell-enriched concanavalin-A-stimulated bovine lymphocytes was studied in vitro. mRNA was isolated from resting and stimulated cells. The amount of polyadenylated RNA increases from 3.6 X 10(-9) to 12 X 10(-9) micrograms/cell during 40 h concanavalin A stimulation. The estimated maximum length of the 3'-poly(A) tract in this RNA is reduced from 240 to 220 residues in stimulated cells. During translation in the rabbit reticulocyte lysate in vitro mRNA from stimulated cells consistently incorporates about 1.6-3 times more radioactivity/micrograms RNA into proteins than mRNA from resting cells. Three translation products have been identified on two-dimensional gels as actin, tubulin and calmodulin. Large quantitative shifts are seen between proteins translated from mRNAs isolated from resting cells and stimulated cells respectively. Actin and calmodulin are already major products from resting cell mRNA. Actin, however, increases about fivefold after stimulation while calmodulin does not change. Tubulin appears in substantial amounts only among stimulated cell mRNA products. Tubulin and calmodulin, on the other hand, remain mainly in the polyadenylated RNA fraction after stimulation while 50% of the actin together with a group of about six other major products is found among proteins translated from non-polyadenylated RNA. We conclude that in lectin-stimulated lymphocytes, besides a general increase in the amount of mRNA, alterations in post-transcriptional processing reactions are active in determining the fate of individual mRNAs.
对富含T细胞的伴刀豆球蛋白A刺激的牛淋巴细胞在体外的分化进行了研究。从静止和受刺激的细胞中分离出mRNA。在伴刀豆球蛋白A刺激的40小时内，多聚腺苷酸化RNA的量从3.6×10⁻⁹增加到12×10⁻⁹微克/细胞。在受刺激的细胞中，这种RNA中3'-多聚腺苷酸尾的估计最大长度从240个残基减少到220个残基。在兔网织红细胞裂解物中进行体外翻译时，受刺激细胞的mRNA始终比静止细胞的mRNA将更多的放射性/微克RNA掺入蛋白质中，掺入量约为1.6 - 3倍。在二维凝胶上已鉴定出三种翻译产物为肌动蛋白、微管蛋白和钙调蛋白。分别从静止细胞和受刺激细胞分离的mRNA翻译的蛋白质之间存在大量的定量变化。肌动蛋白和钙调蛋白已经是静止细胞mRNA的主要产物。然而，肌动蛋白在刺激后增加约五倍，而钙调蛋白没有变化。微管蛋白仅在受刺激细胞的mRNA产物中大量出现。另一方面，微管蛋白和钙调蛋白在刺激后主要保留在多聚腺苷酸化RNA部分，而50%的肌动蛋白以及另外一组约六种其他主要产物则出现在从非多聚腺苷酸化RNA翻译的蛋白质中。我们得出结论，在凝集素刺激的淋巴细胞中，除了mRNA量的普遍增加外，转录后加工反应的改变在决定单个mRNA的命运方面也起着作用。
