Puttaraju M, Perrotta A T, Been M D
Department of Biochemistry, Duke University Medical Center, Durham, NC 27710.
Nucleic Acids Res. 1993 Sep 11;21(18):4253-8. doi: 10.1093/nar/21.18.4253.
A circular trans-acting ribozyme designed to adopt the motif of the hepatitis delta virus (HDV) trans-acting ribozyme was produced. The circular form was generated in vitro by splicing a modified group I intron precursor RNA in which the relative order of the 5' and 3' splice sites, flanking the single HDV-like ribozyme sequence-containing exon, is reversed. Trans-cleavage activity of the circular HDV-like ribozyme was comparable to linear permutations of HDV ribozymes containing the same core sequence, and was shown not to be due to linear contaminants in the circular ribozyme preparation. In nuclear and cytoplasmic extracts from HeLa cells, the circular ribozyme had enhanced resistance to nuclease degradation relative to a linear form of the ribozyme, suggesting that circularization may be a viable alternative to chemical modification as a means of stabilizing ribozymes against nuclease degradation.
一种设计为采用丁型肝炎病毒（HDV）反式作用核酶基序的环状反式作用核酶被制备出来。通过剪接一种修饰的I组内含子前体RNA在体外产生环状形式，其中在包含单个HDV样核酶序列的外显子两侧的5'和3'剪接位点的相对顺序被颠倒。环状HDV样核酶的反式切割活性与含有相同核心序列的HDV核酶的线性排列相当，并且表明不是由于环状核酶制剂中的线性污染物所致。在来自HeLa细胞的核提取物和细胞质提取物中，相对于线性形式的核酶，环状核酶对核酸酶降解具有增强的抗性，这表明环化可能是作为稳定核酶抵抗核酸酶降解的手段的化学修饰的可行替代方法。
