Arbuzov V A
Biokhimiia. 1977 Feb;42(2):338-49.
Metabolism of membrane-bound and free polyribosomal RNAs was studied under conditions of suppressed synthesis of rRNA induced by small doses of actinomycin D. Besides actinomycin D, cycloheximide was used to suppress the protein synthesis. It was demonstrated that administration of cycloheximide and actinomycin D to rats resulted in a stabilization of membrane-bound polysomal mRNA in liver cells. Simultaneously with the action of those antibiotics, free polysomal mRNA was shown to degrade in exactly the same way as in the liver of control animals. Study of poly-A-containing mRNA metabolism showed that during the first hour following rat labelling specific radioactivity of membrane-bound polysomal mRNA was higher than that free polysomal mRNA. Within the interval of 1-5 hours after labelling specific activity of mRNAs of both polysomal fractions reached the same level. In the cell-free system of protein synthesis the membrane-bound polysomes of rat liver cells appeared to be much more active as compared to the free ones. The addition of poly-U matrix to the cell-free system of protein synthesis significantly stimulated the free polysomes activity during 14C-phenylalanine incorporation into polypeptides. Interrelationship of mRNAs of membrane-bound and free polysomes in eucaryotic cells is discussed.
在小剂量放线菌素D诱导的rRNA合成受抑制的条件下，研究了膜结合型和游离型多核糖体RNA的代谢。除放线菌素D外，还使用环己酰亚胺来抑制蛋白质合成。结果表明，给大鼠注射环己酰亚胺和放线菌素D可使肝细胞中膜结合型多核糖体mRNA稳定。在这些抗生素起作用的同时，游离型多核糖体mRNA的降解方式与对照动物肝脏中的完全相同。对含多聚腺苷酸mRNA代谢的研究表明，在大鼠标记后的第一小时内，膜结合型多核糖体mRNA的比放射性高于游离型多核糖体mRNA。在标记后的1至5小时内，两种多核糖体组分的mRNA比活性达到相同水平。在无细胞蛋白质合成系统中，大鼠肝细胞的膜结合型多核糖体比游离型多核糖体活性高得多。向无细胞蛋白质合成系统中添加聚尿苷酸模板，在14C-苯丙氨酸掺入多肽的过程中显著刺激了游离多核糖体的活性。本文讨论了真核细胞中膜结合型和游离型多核糖体mRNA的相互关系。
