Parekh-Olmedo Hetal, Drury Miya, Kmiec Eric B
Department of Biological Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, DE 19716, USA.
Chem Biol. 2002 Oct;9(10):1073-84. doi: 10.1016/s1074-5521(02)00236-3.
Locked nucleic acids (LNAs) are novel base modifications containing a methylene bridge uniting the 2'-oxygen and the 4'-carbon. In this study, LNA-modified single-stranded molecules directed the repair of single base mutations in a yeast chromosomal gene. Using a genetic assay involving a mutant hygromycin-resistance gene, correction of point and frameshift mutations was facilitated by vectors containing an LNA residue on each terminus. Increasing the number of LNA bases on each terminus reduced the correction frequency progressively. When the LNA vector is used in combination with a phosphorothioate-modified vector (74-mer), however, a high level of gene-repair activity occurs; hence, short LNA-based vectors can augment the activity of other types of targeting vectors. These data suggest that oligonucleotides containing locked nucleic acid residues can be used to direct single nucleotide exchange reactions in vivo.
锁核酸（LNA）是一种新型碱基修饰，其包含一个连接2'-氧原子和4'-碳原子的亚甲基桥。在本研究中，LNA修饰的单链分子指导了酵母染色体基因中单碱基突变的修复。使用涉及突变潮霉素抗性基因的遗传检测方法，每个末端含有一个LNA残基的载体促进了点突变和移码突变的校正。增加每个末端LNA碱基的数量会逐渐降低校正频率。然而，当LNA载体与硫代磷酸酯修饰的载体（74聚体）联合使用时，会出现高水平的基因修复活性；因此，基于LNA的短载体可以增强其他类型靶向载体的活性。这些数据表明，含有锁核酸残基的寡核苷酸可用于在体内指导单核苷酸交换反应。
