Furdon P J, Dominski Z, Kole R
Department of Pharmacology, University of North Carolina, Chapel Hill 27599.
Nucleic Acids Res. 1989 Nov 25;17(22):9193-204. doi: 10.1093/nar/17.22.9193.
Three types of 14-mer oligonucleotides were hybridized to human beta-globin pre-mRNA and the resultant duplexes were tested for susceptibility to cleavage by RNase H from E. coli or from HeLa cell nuclear extract. The oligonucleotides contained normal deoxynucleotides, phosphorothioate analogs alternating with normal deoxynucleotides, or one to six methylphosphonate deoxynucleosides. Duplexes formed with deoxyoligonucleotides or phosphorothioate analogs were susceptible to cleavage by RNase H from both sources, whereas a duplex formed with an oligonucleotide containing six methylphosphonate deoxynucleosides alternating with normal deoxynucleotides was resistant. Susceptibility to cleavage by RNase H increased parallel to a reduction in the number of methylphosphonate residues in the oligonucleotide. Stability of the oligonucleotides in the nuclear extract from HeLa cells was also tested. Whereas deoxyoligonucleotides were rapidly degraded, oligonucleotides containing alternating methylphosphonate residues remained unchanged after 70 minutes of incubation. Other oligonucleotides exhibited intermediate stability.
三种14聚体寡核苷酸与人β-珠蛋白前体mRNA进行杂交，然后检测所得双链体对来自大肠杆菌或HeLa细胞核提取物的RNase H切割的敏感性。这些寡核苷酸包含正常脱氧核苷酸、与正常脱氧核苷酸交替的硫代磷酸酯类似物，或一至六个甲基膦酸酯脱氧核苷。与脱氧寡核苷酸或硫代磷酸酯类似物形成的双链体对来自这两种来源的RNase H切割敏感，而与含有六个与正常脱氧核苷酸交替的甲基膦酸酯脱氧核苷的寡核苷酸形成的双链体则具有抗性。对RNase H切割的敏感性随着寡核苷酸中甲基膦酸酯残基数量的减少而平行增加。还测试了寡核苷酸在HeLa细胞核提取物中的稳定性。脱氧寡核苷酸迅速降解，而含有交替甲基膦酸酯残基的寡核苷酸在孵育70分钟后保持不变。其他寡核苷酸表现出中等稳定性。
