作者:Jesper Christensen、François Natt、Jürg Hunziker、Joel Krauser、Hendrik Andres、Piet Swart
DOI:10.1002/jlcr.2919
日期:2012.5.30
A simple procedure is described for full-length single internal [3H]-radiolabeling of oligonucleotides. Previous labeling strategies have been applied to large molecular weight compounds such as proteins and oligonucleotides, for example, iodination and 111In labeling via covalently bounded chelators. However, a procedure has not yet been reported for single internal radiolabeling of oligonucleotides that preserves the molecular structure (3H replacing a 1H). In following our strategy, the radiolabel can be strategically placed within a stable and predetermined internal position of the siRNA. This placement was accomplished by placing a 5-bromouridine or 5-bromo-2′-O-methyluridine phosphoramidite building block into the middle of the antisense strand using standard phosphoramidite chemistry. The deprotected full-length antisense strand was tritium labeled by bromine/tritium exchange, catalyzed by palladium on charcoal in the predetermined 5-position of either uridine or 2′-O-methyluridine. Internal placement of the building block within the oligonucleotide sequence and label placement at 5-position decreases the likelihood of the label to be readily cleaved from the oligonucleotide in vivo, and loss of the label by spontaneous tritium/hydrogen exchange. The tritiated single-stranded and double-stranded RNAs were also shown to be radio and chemically stable for at least 6 months at −80 °C. This allows more than sufficient time to conduct pharmaceutical formulation and pharmacokinetic studies. Copyright © 2012 John Wiley & Sons, Ltd.
描述了寡核苷酸全长单个内部[3H]放射性标记的简单程序。以前的标记策略已应用于蛋白质和寡核苷酸等大分子量化合物,例如通过共价结合螯合剂进行碘化和 111In 标记。然而,尚未报道用于保留分子结构(3H 取代 1H)的寡核苷酸的单一内部放射性标记的程序。按照我们的策略,放射性标记可以策略性地放置在 siRNA 的稳定且预定的内部位置内。这种放置是通过使用标准亚磷酰胺化学将 5-溴尿苷或 5-溴-2'-O-甲基尿苷亚磷酰胺结构单元放置到反义链的中间来完成的。脱保护的全长反义链通过溴/氚交换进行氚标记,由炭载钯催化,在尿苷或 2'-O-甲基尿苷的预定 5 位上进行催化。构建块在寡核苷酸序列内的内部放置和标记在5位的放置降低了标记在体内容易从寡核苷酸上裂解的可能性,以及通过自发的氚/氢交换而损失标记的可能性。氚化单链和双链 RNA 还显示出在 -80°C 下至少 6 个月的放射和化学稳定性。这使得有足够的时间进行药物制剂和药代动力学研究。版权所有 © 2012 约翰·威利父子有限公司