Elements in the 3' untranslated region of procyclin mRNA regulate expression in insect forms of Trypanosoma brucei by modulating RNA stability and translation
Elements in the 3' untranslated region of procyclin mRNA regulate expression in insect forms of Trypanosoma brucei by modulating RNA stability and translation
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DOI：
10.1128/mcb.17.8.4372
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发表时间：
1997-08-01
影响因子：
5.3
通讯作者：
Roditi, I
中科院分区：
文献类型：
--
作者：
Furger, A;Schurch, N;Roditi, I
原细胞周期蛋白是昆虫型布氏锥虫的主要表面糖蛋白。我们以前已经证明，在原环蛋白转录物的3'非翻译区（UTR）中的保守16-mer在原环形式的锥虫中起着阳性元件的作用，对整个297-hase 3' UTR的系统分析现在已经揭示了参与转录后调节的其他元件：需要3' UTR的前30个碱基的阳性元件和在核苷酸101和173之间的至少一个阴性元件缺失任一阳性元件导致蛋白质的量减少>8倍，但mRNA的稳态水平仅减少约2倍，表明调节也发生在翻译水平，与此相反，LII的缺失引起的mRNA和蛋白质的稳态水平的三倍增加，LII-16-mer的双缺失也给出了高水平的表达，这表明16-mer的功能作为一个负元件的抗阻遏物，而不是作为一个独立的激活剂，所有三个元件对RNA周转的影响。当缺失任一阳性元件时，mRNA的半衰期（t（1/2））从类似于50分钟（野生型3' UTR的t（1/2））减少到大约50分钟（野生型3' UTR的t（1/2））。
Procyclins are the major surface glycoproteins of insect forms of Trypanosoma brucei. We have previously shown that a conserved 16-mer in the 3' untranslated region (UTR) of procyclin transcripts functions as a positive element in procyclic-form trypanosomes, A systematic analysis of the entire 297-hase 3' UTR has now revealed additional elements which are involved in posttranscriptional regulation: a positive element which requires the first 30 bases of the 3' UTR and at least one negative element between nucleotides 101 and 173 (the LII domain), Deletion of either positive element resulted in a >8-fold reduction in the amount of protein but only an similar to 2-fold decrease in the steady-state level of mRNA, suggesting that regulation also occurred at the level of translation, In contrast, deletion of LII caused a threefold increase in the steady-state levels of both the mRNA and protein, LII-16-mer double deletions also gave high levels of expression, suggesting that the 16-mer functions as an antirepressor of the negative element rather than as an independent activator, All three elements have an effect on RNA turnover. When either positive element was deleted, the half-life (t(1/2)) of the mRNA was reduced from similar to 50 min (the t(1/2) of the wild-type 3' UTR) to