RNase G (CafA protein) and RNase E are both required for the 5′ maturation of 16S ribosomal RNA
RNase G (CafA protein) and RNase E are both required for the 5′ maturation of 16S ribosomal RNA
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DOI：
10.1093/emboj/18.10.2878
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发表时间：
1999-05-17
期刊：
影响因子：
11.4
通讯作者：
Deutscher, MP
中科院分区：
文献类型：
--
作者：
Li, ZW;Pandit, S;Deutscher, MP
在大肠杆菌中，rRNA操纵子转录为30S前体分子，必须进行广泛的加工才能产生成熟的16S、23S和5S rRNA，而已知RNaseIII切割初级转录产物以分离单个rRNA，有关形成其成熟的3‘和5’末端所需的二级加工反应的信息很少，我们现在发现，内切核酸酶RNase E的失活会减缓17S RNaseIII裂解产物的16S RNA的体内成熟，此外，在没有CAFA蛋白的情况下，16S RNA的形成也会减慢，但在这种情况下，16.3S中间产物会积累。当RNaseE和CAFA均失活时，16S rRNA的5‘成熟完全受阻。相反，3‘端的成熟基本不受影响，在双突变体中积累的5’端未加工的前体可以组装成30S和70S的核糖体，前体也可以在体外被RNaseE和CAFA处理。这些数据表明，RNaseE和CAFA蛋白都是16SRRNA 5‘端两步连续成熟所必需的，CAFA蛋白是一种新的核糖核酸酶。我们建议将其更名为RNaseG。
In Escherichia coli, rRNA operons are transcribed as 30S precursor molecules that must be extensively processed to generate mature 16S, 23S and 5S rRNA, While it is known that RNase III cleaves the primary transcript to separate the individual rRNAs, there is little information about the secondary processing reactions needed to form their mature 3' and 5' termini, We have now found that inactivation of the endoribonuclease RNase E slows down lit vivo maturation of 16S RNA from the 17S RNase III cleavage product, Moreover, in the absence of CafA protein, a homolog of RNase E, formation of 16S RNA also slows down, but in this case a 16.3S intermediate accumulates. When both RNase E and CafA are inactivated, 5' maturation of 16S rRNA is completely blocked. In contrast, 3' maturation is essentially unaffected, The 5' unprocessed precursor that accumulates in the double mutant can he assembled into 30S and 70S ribosomes, Precursors also can be processed in vitro by RNase E and CafA, These data indicate that both RNase E and CafA protein are required for a two step, sequential maturation of the 5' end of 16S rRNA, and that CafA protein is a new ribonuclease. We propose that it be renamed RNase G.