Liebhaber S A, Kan Y W
J Biol Chem. 1982 Oct 25;257(20):11852-5.
The relative translational efficiency of the two human alpha-globin mRNAs, alpha 1 and alpha 2, was measured in vitro in a rabbit reticulocyte lysate system. To differentiate the translational products of these two mRNAs which normally encode an identical alpha-globin protein product, we used reticulocyte mRNA from a recently described Chinese subject. In this subject, an electrophoretically distinct alpha-globin mutant is encoded at the alpha 2 locus and both the alpha 1- and alpha 2-globin genes are deleted from the homologous chromosome (--/alpha 125Pro alpha). As in normal controls, the concentration of alpha 2-globin mRNA exceeded alpha 1 by approximately 3-fold. However, alpha 1- and alpha 2-globin proteins were synthesized by this reticulocyte mRNA at equal rates. This data suggests that the equal expression of the two alpha-globin genes observed in human erythrocytes results from a balance between the 3-fold excess of alpha 2-globin mRNA and a 3-fold higher translational efficiency of alpha 1-globin mRNA. The disparate translational efficiencies of the two alpha-globin mRNAs may be determined by the divergent structure of their 3' noncoding regions.
在兔网织红细胞裂解物系统中对两种人类α-珠蛋白mRNA（α1和α2）的相对翻译效率进行了体外测定。为了区分这两种通常编码相同α-珠蛋白产物的mRNA的翻译产物，我们使用了来自最近描述的一名中国受试者的网织红细胞mRNA。在该受试者中，α2位点编码一种电泳上不同的α-珠蛋白突变体，同源染色体上的α1和α2珠蛋白基因均缺失（--/α125Proα）。与正常对照一样，α2-珠蛋白mRNA的浓度比α1高约3倍。然而，这种网织红细胞mRNA以相等的速率合成α1和α2珠蛋白。该数据表明，在人类红细胞中观察到的两种α-珠蛋白基因的等量表达是由于α2-珠蛋白mRNA的3倍过量与α1-珠蛋白mRNA高3倍的翻译效率之间的平衡所致。两种α-珠蛋白mRNA不同的翻译效率可能由其3'非编码区的不同结构决定。
