Boudvillain M, Guérin M, Dalbiès R, Saison-Behmoaras T, Leng M
Centre de Biophysique Moleculaire, CNRS, Orleans, France.
Biochemistry. 1997 Mar 11;36(10):2925-31. doi: 10.1021/bi962695f.
In the reaction between trans-diamminedichloroplatinum(II) and single-stranded oligo(2'-O-methyl ribonucleotide)s containing the sequence GNG (N being a nucleotide residue), the 1,3-trans-{Pt-(NH3)2[GNG]} cross-links are formed. The 1,3-intrastrand cross-links are inert within the single-stranded oligonucleotides. By contrast, they rearrange into interstrand cross-links when the platinated oligonucleotides are paired with their complementary RNA strands. The rate of the interstrand cross-linking reaction depends upon the sequence facing the intrastrand cross-links. When the complementary sequences are 5'-CN'C (N' being a nucleotide), the rates are rather slow (T1/2 >/= 3 h at 37 degrees C). The rearrangement of the intrastrand cross-links into interstrand cross-links can be achieved in a few minutes when the triplets facing the intrastrand cross-links are replaced by doublet 5'-UA or 5'-CA. In vitro, the specificity of the cross-linking reaction between a platinated oligo(2'-O-methyl ribonucleotide) and its target sequence (containing the 5'-CA doublet) located within the coding region of Ha-ras mRNA is demonstrated by steric blocking of reverse transcriptase and translation machinery. Within the HBL100ras1 cells, this platinated oligonucleotide binds specifically and irreversibly to the cognate Ha-ras mRNA. It also inhibits the proliferation of the HBL100ras1 cells in a dose-dependent manner. The fast and specific interstrand cross-linking reaction triggered by the formation of a double helix between platinated oligo(2'-O-methyl ribonucleotide)s and RNA enhances the potential of the oligonucleotides which do not induce mRNA cleavage by RNase H, to modulate gene expression by steric blocking of the translation machinery.
在反式二氨二氯铂（II）与含有GNG序列（N为核苷酸残基）的单链寡聚（2'-O-甲基核糖核苷酸）之间的反应中，形成了1,3-反式-{Pt-(NH3)2[GNG]}交联。1,3-链内交联在单链寡核苷酸内是惰性的。相比之下，当铂化寡核苷酸与它们的互补RNA链配对时，它们会重排成链间交联。链间交联反应的速率取决于面对链内交联的序列。当互补序列为5'-CN'C（N'为核苷酸）时，反应速率相当缓慢（37℃下T1/2≥3小时）。当面对链内交联的三联体被双峰5'-UA或5'-CA取代时，链内交联重排成链间交联可以在几分钟内完成。在体外，通过逆转录酶和翻译机制的空间位阻证明了铂化寡聚（2'-O-甲基核糖核苷酸）与其位于Ha-ras mRNA编码区内的靶序列（含有5'-CA双峰）之间交联反应的特异性。在HBL100ras1细胞内，这种铂化寡核苷酸特异性且不可逆地结合到同源Ha-ras mRNA上。它还以剂量依赖的方式抑制HBL100ras1细胞的增殖。由铂化寡聚（2'-O-甲基核糖核苷酸）与RNA之间形成双螺旋引发的快速且特异性的链间交联反应增强了那些不诱导mRNA被RNase H切割的寡核苷酸通过翻译机制的空间位阻来调节基因表达的潜力。
