Chang Yuo-Sheng, Lo Chi-Wei, Sun Fang-Chun, Chang Margaret Dah-Tsyr, Lai Yiu-Kay
Institute of Biotechnology, Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan 30013, ROC.
Biochem Biophys Res Commun. 2006 May 26;344(1):37-44. doi: 10.1016/j.bbrc.2006.03.157.
In mammals, two major Hsp90 isoforms (Hsp90alpha and Hsp90beta) have been identified and found to be highly conserved among different species. However, the expression control of Hsp90 isoforms at both transcriptional and translational levels is largely unknown. Herein, we quantitatively investigate the changes in the total mRNA and inductive protein levels of Hsp90alpha and Hsp90beta in rat gliosarcoma cells treated with geldanamycin (GA). The stability of mRNA and protein was estimated. The translational efficiency of Hsp90 isoforms was measured employing in vitro translation techniques. It was found that Hsp90alpha was more inducible than Hsp90beta after GA treatment, whereas the hsp90alpha mRNA level was lower than that of hsp90beta. In addition, higher translational efficiency of hsp90alpha mRNA was observed, suggesting that translational control played an important role. Taken together, our results indicate that differential expression between Hsp90alpha and Hsp90beta is a consequence of both distinct mRNA profiles and differential translation processes.
在哺乳动物中，已鉴定出两种主要的热休克蛋白90（Hsp90）亚型（Hsp90α和Hsp90β），并发现它们在不同物种间高度保守。然而，Hsp90亚型在转录和翻译水平上的表达调控在很大程度上尚不清楚。在此，我们定量研究了用格尔德霉素（GA）处理的大鼠胶质肉瘤细胞中Hsp90α和Hsp90β的总mRNA水平和诱导蛋白水平的变化。评估了mRNA和蛋白质的稳定性。采用体外翻译技术测定了Hsp90亚型的翻译效率。结果发现，GA处理后Hsp90α比Hsp90β更易被诱导，而hsp90α mRNA水平低于hsp90β。此外，观察到hsp90α mRNA的翻译效率更高，表明翻译调控起重要作用。综上所述，我们的结果表明，Hsp90α和Hsp90β之间的差异表达是不同mRNA谱和差异翻译过程共同作用的结果。
