RNAi in mouse oocytes and preimplantation embryos: effectiveness of hairpin dsRNA

RNA interference (RNAi), the targeted mRNA degradation by double-stranded RNA (dsRNA), is a useful tool for studying gene function in several organisms. Here we report results of experiments with mammalian dsRNA expression vectors that are suitable to study gene function in mouse oocytes and preimplantation embryos. The plasmid vectors were constructed to contain the SV40 small intron, EGFP coding sequence to permit detection of expression, and an inverted repeat to mos mRNA that would form a hairpin dsRNA. Results of the experiments indicated that (i) hairpin dsRNA was just as effective as dsRNA (i.e., annealed sense and antisense RNA) in promoting the destruction of targeted mRNA, (ii) the EGFP marker could be expressed from the construct, and (iii) the distance of the SV40 intron from the inverted repeat was critical for the transcribed RNA to function in RNAi.