Cazenave C, Chevrier M, Nguyen T T, Hélène C
Laboratoire de Biophysique, Muséum National d'Histoire Naturelle, INSERM U.201, Paris, France.
Nucleic Acids Res. 1987 Dec 23;15(24):10507-21. doi: 10.1093/nar/15.24.10507.
End-labelled oligodeoxynucleotides were injected into Xenopus laevis oocytes and their degradation products were analysed by high-performance ion-exchange liquid chromatography after various times of incubation. The oligonucleotides were synthesised with either the natural [beta] anomers or the synthetic [alpha] anomers of deoxynucleotide units. Oligo-[beta] deoxynucleotides are short-lived inside oocytes (half-life approximately equal to 10 min). Covalent attachment of an intercalating agent to the 3'-phosphate and of a methylthiophosphate group at the 5'-end protects oligodeoxynucleotides against 3'- and 5'-exonucleases, respectively. The half-life of such substituted oligodeoxynucleotides is increased to 40 minutes. Oligo-[alpha]-deoxynucleotides are quite resistant to both endo and exonucleases inside Xenopus oocytes. After 8 hours only 40% of a 16-mer oligo-[alpha]-deoxynucleotide were hydrolysed. The rapid degradation of oligo-[beta]-deoxynucleotides suggests that efficient inhibition of translation in Xenopus oocytes involves an RNase H-induced hydrolysis of mRNAs hybridized to oligo-[beta]-deoxynucleotides.
将末端标记的寡脱氧核苷酸注射到非洲爪蟾卵母细胞中,在不同孵育时间后,通过高效离子交换液相色谱分析其降解产物。寡核苷酸是用脱氧核苷酸单元的天然β异头物或合成α异头物合成的。寡-β-脱氧核苷酸在卵母细胞内寿命较短(半衰期约为10分钟)。将嵌入剂共价连接到3'-磷酸基团上,并在5'-末端连接一个甲基硫代磷酸基团,分别保护寡脱氧核苷酸免受3'-和5'-外切核酸酶的作用。这种取代的寡脱氧核苷酸的半衰期增加到40分钟。寡-α-脱氧核苷酸在非洲爪蟾卵母细胞内对内切核酸酶和外切核酸酶都相当耐受。8小时后,16聚体寡-α-脱氧核苷酸只有40%被水解。寡-β-脱氧核苷酸的快速降解表明,在非洲爪蟾卵母细胞中有效抑制翻译涉及核糖核酸酶H诱导的与寡-β-脱氧核苷酸杂交的mRNA的水解。