Huez G, Bruck C, Cleuter Y
Proc Natl Acad Sci U S A. 1981 Feb;78(2):908-11. doi: 10.1073/pnas.78.2.908.
HeLa human cells were injected with a natural mixture of rabbit alpha and beta globin mRNA. They were incubated for 6 hr with [35S]methionine either immediately after injection or 20 hr later. The labeled proteins in the injected cells were analyzed by fluorography of two-dimensional electrophoresis gels. By using this procedure, it was possible to show that, during the first few hours after injection, both alpha and beta globin molecules are synthesized with an alpha to beta ratio approximately equal to 0.6. The rate of synthesis of alpha globin decreased significantly faster than that of beta globin over a 26-hr period after injection of the two mRNAs. It thus seems that two messenger RNAs coding for closely related polypeptides possess a markedly different translational stability. When deadenylylated rabbit globin mRNAs were injected into HeLa cells, no globin synthesis could be detected by the techniques used. We conclude that the translational half-life of mRNAs lacking poly(A) is very short in these cells. It is thus clear that the poly(A) segment is required to ensure stability to globin mRNA in somatic cells as in Xenopus oocytes.
将兔α和β珠蛋白mRNA的天然混合物注射到HeLa人细胞中。注射后立即或20小时后，用[35S]甲硫氨酸孵育6小时。通过二维电泳凝胶的荧光自显影分析注射细胞中的标记蛋白。通过使用该程序，可以表明，在注射后的最初几个小时内，α和β珠蛋白分子均以大约等于0.6的α与β比率合成。在注射两种mRNA后的26小时内，α珠蛋白的合成速率比β珠蛋白的合成速率显著更快地下降。因此，似乎编码密切相关多肽的两种信使RNA具有明显不同的翻译稳定性。当将去腺苷酸化的兔珠蛋白mRNA注射到HeLa细胞中时，使用所采用的技术无法检测到珠蛋白的合成。我们得出结论，在这些细胞中，缺乏聚腺苷酸的mRNA的翻译半衰期非常短。因此很明显，聚腺苷酸片段对于确保体细胞中珠蛋白mRNA的稳定性是必需的，就像在非洲爪蟾卵母细胞中一样。
