AUTOREGULATORY FRAMESHIFTING IN DECODING MAMMALIAN ORNITHINE DECARBOXYLASE ANTIZYME
AUTOREGULATORY FRAMESHIFTING IN DECODING MAMMALIAN ORNITHINE DECARBOXYLASE ANTIZYME
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DOI：
10.1016/0092-8674(95)90450-6
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发表时间：
1995-01-13
期刊：
影响因子：
64.5
通讯作者：
HAYASHI, S
中科院分区：
文献类型：
--
作者：
MATSUFUJI, S;MATSUFUJI, T;HAYASHI, S
大鼠抗酶基因的表达需要程序化的核糖体移码。一种新的自动调节机制能够根据多胺的细胞浓度调节移码。抗酶与多胺合成中的关键酶鸟氨酸脱羧酶结合并使其不稳定，快速降解增强，从而完成调节回路。使用网织红细胞裂解物的融合构建体的体外实验表明，在亚精胺的最佳浓度下，多胺依赖性表达的移码效率为19%。移码为+1，发生在起始框终止子之前的密码子处。起始框架的终止密码子和mRNA下游的假结都具有刺激作用。移位位点序列UCC-UGA-U与其他已知的移码位点不相似。该机制似乎不涉及肽基-tRNA在新框架中的重新配对，而是阅读或第四个碱基的封闭。
Rat antizyme gene expression requires programmed, ribosomal frameshifting. A novel autoregulatory mechanism enables modulation of frameshifting according to the cellular concentration of polyamines. Antizyme binds to, and destabilizes, ornithine decarboxylase, a key enzyme in polyamine synthesis, Rapid degradation ensues, thus completing a regulatory circuit. In vitro experiments with a fusion construct using reticulocyte lysates demonstrate polyamine-dependent expression with a frameshift efficiency of 19% at the optimal concentration of spermidine. The frameshift is +1 and occurs at the codon just preceding the terminator of the initiating frame. Both the termination codon of the initiating frame and a pseudoknot downstream in the mRNA have a stimulatory effect. The shift site sequence, UCC-UGA-U, is not similar to other known frameshift sites. The mechanism does not seem to involve re-pairing of peptidyl-tRNA in the new frame but rather reading or occlusion of a fourth base.