Compounds and oligomeric compounds comprising novel nucleobases
申请人:——
公开号:US20040033973A1
公开(公告)日:2004-02-19
The present invention relates to nucleoside compositions comprising novel nucleobases and oligomeric compounds comprising at least one such nucleoside. These oligomeric compounds typically have enhanced binding affinity properties compared to oligomeric compounds without the modification. The oligomeric compounds are useful, for example, for investigative and therapeutic purposes.
Herein we describe the synthesis of 4'-thio-dTTP (1) and 4'-thio-dCTP (2) and their susceptibility for PCR amplification. Double stranded 4'-thioDNAs were amplified sufficiently by KOD dash DNA polymerase under appropriate conditions. Through this PCR study, it was shown that not only DNA-directed 4'-thioDNA synthesis but also 4'-thioDNA-directed 4'-thioDNA synthesis occurred in the presence of 1 and/or 2. We then tested the ability of the resulting 4'-thioDNAs to act as templates for transcription. In this experiment, the 4'-thioDNAs as templates afforded RNA in 38-49% yield relative to the case of the natural DNA template. We further investigated whether transcription occurred in mammalian cells. As a result, not only natural DNA but also 4'-thioDNAs were transcribed to afford a shRNA which showed gene-silencing effects via RNAi machinery.