Department of Polymer Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 602-0841, Japan.
In order to selectively regulate mRNA having a point mutation, the photo-reactive antisense oligonucleotides were developed. Two types of photo-reactive oligonucleotides containing adenosine whose 2'-OH was modified with 4,5',8-trimethylpsoralen (psoralen) were synthesized (2'-Ps-oligo). One contains psoralen via a methylene linkage (2'-Ps-met), and the other via an amidomethylene linkage (2'-Ps-amd). 2'-Ps-oligos were then subjected to the photo-cross-linking reaction. 2'-Ps-met cross-linked to the complementary RNA and scarcely did to the RNA having a single mismatch base. Contrarily, 2'-Ps-amd did not cross-link to both RNA strands. These results suggest the structure of the linkage might affect the efficiency of the photo-cross-linking.