Musters W, Conçalves P M, Boon K, Raué H A, van Heerikhuizen H, Planta R J
Biochemisch Laboratorium, Vrije Universiteit de Boelelaan, Amsterdam, The Netherlands.
Proc Natl Acad Sci U S A. 1991 Feb 15;88(4):1469-73. doi: 10.1073/pnas.88.4.1469.
Using the "tagged" rRNA gene system, which allows in vivo mutational analysis of Saccharomyces cerevisiae rRNA, we studied the role of two distinct structural elements of 26S rRNA in ribosome biogenesis and function--namely, the evolutionarily highly conserved "GTPase center" located in domain II and the eukaroyote-specific variable region V9 in domain III. Replacement of the S. cerevisiae GTPase center with its counterpart from Escherichia coli did not affect the assembly of the mutant 26S rRNA into functional (as judged by their polysomal distribution) 60S subunits, indicating that the E. coli GTPase center functions efficiently in the context of the heterologous rRNA. Removal of most of the S. cerevisiae V9 region or replacement of this segment by the equivalent segment from mouse 28S rRNA also did not affect the formation of functional 60S subunits carrying the mutant 26S rRNA. Therefore, the V9 region does not seem to play a role in the biological functioning of the yeast 60S subunits, and these subunits appear to be able to accommodate V9 regions of various size and secondary structure without apparent loss of function.
利用“标记”的rRNA基因系统，该系统可对酿酒酵母rRNA进行体内突变分析，我们研究了26S rRNA的两个不同结构元件在核糖体生物发生和功能中的作用，即位于结构域II的进化上高度保守的“GTP酶中心”和结构域III中的真核生物特异性可变区V9。用大肠杆菌的对应物替换酿酒酵母的GTP酶中心，并不影响突变型26S rRNA组装成功能性的（根据其多核糖体分布判断）60S亚基，这表明大肠杆菌的GTP酶中心在异源rRNA的背景下能有效发挥作用。去除酿酒酵母V9区域的大部分或用小鼠28S rRNA的等效片段替换该片段，也不影响携带突变型26S rRNA的功能性60S亚基的形成。因此，V9区域似乎在酵母60S亚基的生物学功能中不起作用，并且这些亚基似乎能够容纳各种大小和二级结构的V9区域，而不会明显丧失功能。
