CHEMICAL SYNTHESIS OF OLIGONUCLEOTIDE ANALOGUES

与mRNA或双链DNA互补的合成寡核苷酸 作为削弱活细胞中基因表达的手段， 设计和开发用于治疗药物寡核苷酸类似物的动力 目的 与天然寡核苷酸不同， 具有交替的（3 ′ 3 ′）-和（5 ′ 5 ′）-核苷酸间磷酸二酯 连接不容易被核酸酶识别， 这种固有的溶核稳定性，可以在反义核酸中找到应用。 实验 一个简化的化学已开发的合成 - 核苷前体。 固相合成一种， 具有交替的（3 '3'）-和（5 '5'）- 核苷酸间磷酸二酯键（24-mer），与 与编码第二外显子的剪接受体位点重叠的区域 HIV-1达特基因产物。 该低聚物 与其互补的未修饰的DNA链杂交，形成了一个 复合物的Tm（53 C）与用类似的 由相应的β-硫代磷酸酯组成的杂合体 和其互补的未修饰的DNA链（Tm= 56 C），但低于 在相同条件下用天然DNA双链体（Tm= 66 ℃）观察到。 因此，-寡脱氧核糖核苷酸应该表现出相似的序列- 特异性作为研究充分的寡脱氧核糖核苷 硫代磷酸酯。 为了提供对核酸酶更好的抗性， 仅具有硫代磷酸酯键的寡脱氧核糖核苷酸 或者在每个末端仅合成了两个这样的键。 这些寡核苷酸类似物在抑制肿瘤细胞增殖方面的效力和功效 HIVIIIb在人T细胞系中复制受到抑制 调查 对细胞系的细胞毒性作用同时 评估。

Synthetic oligonucleotides complementary to mRNA or double-stranded DNA as a means to impair gene expression in living cells has provided the impetus to design and develop oligonucleotide analogues for therapeutic purposes. Unlike natural oligonucleotides, ,-oligodeoxyribonucleotides having alternative (3' 3')-and (5' 5')-internucleotidic phosphodiester linkages are not readily recognized by nucleases and, as a consequence of this inherent nucleolytic stability, may find application in antisense experiments. A simplified chemistry has been developed for the synthesis of -nucleoside precursors. The solid-phase synthesis of an ,- oligodeoxyribonucleotide having alternating (3'3')-and (5'5')- internucleotidic phosphodiester linkages (24-mer), complementary to a region overlapping the splice acceptor site of the second exon encoding the HIV-1 Tat gene product, has been accomplished. This oligomer hybridized to its complementary unmodified DNA strand and formed a complex having a Tm (53C) comparable to that obtained with a similar hybrid composed of the corresponding -oligonucleoside phosphorothioate and its complementary unmodified DNA strand (Tm=56C) but lower than that observed with the native DNA duplex (Tm=66C) under the same conditions. Thus, ,-oligodeoxyribonucleotides should exhibit similar sequence- specificity as the well-studied -oligodeoxyribonucleoside phosphorothioates. To provide better resistance against nucleases, ,- oligodeoxyribonucleotides having exclusively phosphorothioate linkages or only two these linkages at each terminus have also been synthesized. The potency and efficacy of these oligonucleotide analogues at inhibiting the replication of HIVIIIb in a human T-cell line are under investigation. Cytotoxic effects on the cell line are simultaneously assessed.