Ribosomal protein L32 of Saccharomyces cerevisiae regulates both splicing and translation of its own transcript.
Ribosomal protein L32 of Saccharomyces cerevisiae regulates both splicing and translation of its own transcript.
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DOI：
10.1016/s0021-9258(19)36568-8
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发表时间：
1993-09
期刊：
影响因子：
--
通讯作者：
M. Dabeva;J. R. Warner
中科院分区：
文献类型：
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作者：
M. Dabeva;J. R. Warner
酿酒酵母的核糖体蛋白 L32 显然是通过与主要由 5' 外显子组成的结构相互作用来调节其自身转录物 (1, 2) 的剪接。然而，即使在过量产生 L32 mRNA 的菌株中，例如从该基因的 cDNA 拷贝来看，在短暂的脉冲标记后几乎观察不到 L32 的积累。当 RPL32 mRNA 的 5' 前导序列被外源前导序列取代时，脉冲标记的 L32 的量增加数倍，表明 L32 通过 5' 区域中的序列调节其自身 mRNA 的翻译。这一结论通过以下观察得到证实：在携带L32前导序列与LacZ编码序列融合的嵌合基因的细胞中，尽管L32-lacZ融合mRNA加倍，但过表达L32本身的第二个基因的存在使β-半乳糖苷酶水平降低了50%，这可能是由于信息的稳定。 5'前导序列内的突变消除了剪接的调节，也消除了翻译的调节，这表明L32的翻译调节涉及与所提议的剪接调节相似的结构。在过量产生 L32-mRNA 的细胞中，大约一半的过量 mRNA 存在于 < 25 S 的核糖核蛋白中，与核糖体颗粒无关。其余大部分存在于 80-120 S 的核糖核蛋白中。
Ribosomal protein L32 of Saccharomyces cerevisiae regulates the splicing of its own transcript (1, 2) apparently by interacting with a structure composed largely of the 5' exon. However, even in strains overproducing L32 mRNA, e.g. from a cDNA copy of the gene, little accumulation of L32 is observed after a brief pulse label. When the 5' leader of the RPL32 mRNA is replaced by an exogenous leader, the amount of pulse-labeled L32 increases severalfold, suggesting that L32 regulates the translation of its own mRNA, acting through sequences in the 5' region. This conclusion was confirmed by the observation that in cells carrying a chimeric gene in which the L32 leader is fused to LacZ coding sequences, the presence of a second gene that overexpresses L32 itself reduces the level of beta-galactosidase by 50%, in spite of a doubling of L32-lacZ fusion mRNA, presumably due to stabilization of the message. Mutations within the 5' leader that abolish the regulation of splicing also abolish the regulation of translation, suggesting that the regulation of translation by L32 involves a structure similar to that proposed for the regulation of splicing. In cells overproducing L32-mRNA about half the excess mRNA was found in ribonucleoproteins of < 25 S, unassociated with ribosomal particles. Much of the rest was found in ribonucleoproteins of 80-120 S.