SUBSTRATE-SPECIFICITY OF THE DSRNA UNWINDING MODIFYING ACTIVITY
SUBSTRATE-SPECIFICITY OF THE DSRNA UNWINDING MODIFYING ACTIVITY
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DOI：
10.1002/j.1460-2075.1991.tb04916.x
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发表时间：
1991-11-01
期刊：
影响因子：
11.4
通讯作者：
LIEBHABER, SA
中科院分区：
文献类型：
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作者：
NISHIKURA, K;YOO, C;LIEBHABER, SA
双链RNA（dsRNA）解旋/修饰活性，其存在于广泛的真核细胞中，先前已显示在分子间dsRNA内将高达50%的腺苷残基转化为肌苷。在本研究中，我们报告说，这种活动也修改，虽然效率稍低，分子内的合成RNA的双链区域。我们的研究结果拓宽了活性的可能生物底物的范围，因为存在于真核生物以及病毒转录物中的许多茎和环型RNA二级结构（分子内dsRNA）可以潜在地用作底物。此外，我们发现dsRNA解旋/修饰活性需要至少15-20个碱基对（bp）的双链区域用于底物识别。此外，发现修饰效率严重依赖于双链区域的长度;当大小降低到100 bp以下时，其急剧下降。我们的研究结果表明，有效的修饰可能只发生在相对较长（> 100 bp）的dsRNA上，这可能是因为必须结合多个拷贝的酶。
Double-stranded RNA (dsRNA) unwinding/modifying activity, which is present in a wide range of eukaryotic cells, has been previously shown to convert up to 50% of adenosine residues to inosines within intermolecular dsRNA. In the present study, we report that this activity also modifies, though slightly less efficiently, intramolecular double-stranded regions of synthetic RNAs. Our results widen the range of the possible biological substrates for the activity since many stem and loop type RNA secondary structures (intramolecular dsRNA), present in eukaryotic as well as viral transcripts, can potentially serve as substrates. In addition, we have found that the dsRNA unwinding/modifying activity requires a double-stranded region of at least 15-20 base pairs (bp) for substrate recognition. Furthermore, modification efficiency was found to be critically dependent on the length of the double-stranded region; as the size decreased below 100 bp, it dropped precipitously. Our results suggest that efficient modification may occur only with relatively long (> 100 bp) dsRNA, perhaps because multiple copies of the enzyme must be bound.