VERTEBRATE MESSENGER-RNAS WITH A 5'-TERMINAL PYRIMIDINE TRACT ARE CANDIDATES FOR TRANSLATIONAL REPRESSION IN QUIESCENT CELLS - CHARACTERIZATION OF THE TRANSLATIONAL CIS-REGULATORY ELEMENT
VERTEBRATE MESSENGER-RNAS WITH A 5'-TERMINAL PYRIMIDINE TRACT ARE CANDIDATES FOR TRANSLATIONAL REPRESSION IN QUIESCENT CELLS - CHARACTERIZATION OF THE TRANSLATIONAL CIS-REGULATORY ELEMENT
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DOI：
10.1128/mcb.14.6.3822
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发表时间：
1994-06-01
影响因子：
5.3
通讯作者：
MEYUHAS, O
中科院分区：
文献类型：
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作者：
AVNI, D;SHAMA, S;MEYUHAS, O
哺乳动物核糖体蛋白（rp）mRNA的翻译在非生长细胞中被选择性抑制。该应答通过位于这些mRNA的5'非翻译区的调节元件介导，并且包括5'末端寡嘧啶段（5' TOP）。为了进一步表征翻译顺式调控元件，我们监测了各种内源性和异源性mRNA或来自转染的嵌合基因的杂交转录物的翻译行为。在正常生长或在各种生理条件下生长停滞的细胞中评估这些mRNA的翻译效率。我们的实验结果表明：（1）哺乳动物rp mRNA的翻译在两栖动物细胞中受到适当的调控，同样地，两栖动物rp mRNA在哺乳动物细胞中也受到调控，这表明rp mRNA翻译调控所需的所有元件在脊椎动物中是保守的;（ii）选择性翻译控制不限于rp mRNA，因为编码天然存在的泛素-rp融合蛋白和延伸因子Icu的mRNA含有5 ′ TOP，也符合这种调控模式;（iii）大鼠rpP 2 mRNA在其5' TOP中仅含有5个嘧啶，然而这种mRNA以与具有8个或更多个嘧啶的5' TOP的其它rp mRNA相同的方式被间接控制;（iv）这种调控模式的完全表现似乎需要5' TOP和紧邻下游的序列;和（v）来自rpL 32 mRNA的完整翻译调节元件即使在前面有单个A残基时也不能发挥其调节特性。
The translation of mammalian ribosomal protein (rp) mRNAs is selectively repressed in nongrowing cells. This response is mediated through a regulatory element residing in the 5' untranslated region of these mRNAs and includes a 5' terminal oligopyrimidine tract (5' TOP). To further characterize the translational cis-regulatory element, we monitored the translational behavior of various endogenous and heterologous mRNAs or hybrid transcripts derived from transfected chimeric genes. The translational efficiency of these mRNAs was assessed in cells that either were growing normally or were growth arrested under various physiological conditions. Our experiments have yielded the following results: (i) the translation of mammalian rp mRNAs is properly regulated in amphibian cells, and likewise, amphibian rp mRNA is regulated in mammalian cells, indicating that all of the elements required for translation control of rp mRNAs are conserved among vertebrate classes; (ii) selective translational control is not confined to rp mRNAs, as mRNAs encoding the naturally occurring ubiquitin-rp fusion protein and elongation factor Icu, which contain a 5' TOP, also conform this mode of regulation; (iii) rat rpP2 mRNA contains only five pyrimidines in its 5' TOP, yet this mRNA is translationally controlled in the same fashion as other rp mRNAs with a 5' TOP of eight or more pyrimidines; (iv) full manifestation of this mode of regulation seems to require both the 5' TOP and sequences immediately downstream; and (v) an intact translational regulatory element from rpL32 mRNA fails to exert its regulatory properties even when preceded by a single A residue.