Stevens A
Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831-8080, USA.
Biochem Biophys Res Commun. 1998 Oct 20;251(2):501-8. doi: 10.1006/bbrc.1998.9499.
Structure-specific nucleases called 5' flap endonucleases cleave unannealed 5' arms of template-primer DNA model substrates at the start of the duplex and are involved in Okazaki fragment processing during DNA synthesis. To determine the possible use of the enzymes in RNA structure analysis, the cleavage of synthetic and native RNAs was examined using flap endonuclease 1 (Fen1) of HeLa cells. RNAs are cleaved at about 20% of the rate of DNA model substrates, and most of the cleavage sites are within 200 nucleotides of the 5' end. Hydrolysis of MFA2 mRNA of yeast shows that the cleavages are at the start of five possible stem structures of a folded secondary structure predicted on the basis of both chemical and enzymatic structure probing. 16S ribosomal RNA of Escherichia coli is cleaved at several 5' stem structures of its phylogenetically predicted folded structure. This type of RNA cleavage specificity may be very useful in secondary structure analysis in the future and also may be used by cells for specific 5' end-geared RNA cleavages.
被称为5' 翼片内切核酸酶的结构特异性核酸酶在双链体起始处切割模板-引物DNA模型底物未退火的5' 臂，并参与DNA合成过程中的冈崎片段加工。为了确定这些酶在RNA结构分析中的可能用途，使用来自HeLa细胞的翼片内切核酸酶1（Fen1）检测了合成RNA和天然RNA的切割情况。RNA的切割速率约为DNA模型底物的20%，并且大多数切割位点在5' 端的200个核苷酸范围内。酵母MFA2 mRNA的水解表明，切割发生在基于化学和酶促结构探测预测的折叠二级结构的五个可能茎结构的起始处。大肠杆菌的16S核糖体RNA在其系统发育预测的折叠结构的几个5' 茎结构处被切割。这种类型的RNA切割特异性在未来的二级结构分析中可能非常有用，并且细胞也可能将其用于特定的5' 端导向的RNA切割。
