FIGURE 4.

RT-PCR analysis of Mos mRNA in oocytes injected with EGFP dsRNA and chimeric Mos–EGFP mRNA. (A) Absence of Mos mRNA degradation in oocytes microinjected with chimeric transcript and/or EGFP dsRNA. GV-intact oocytes were microinjected with ∼7.5 × 10⁶ molecules of chimeric transcript and/or EGFP dsRNA and then cultured in the presence of IBMX for 20 h. RNA was then isolated and the relative amount of Mos and Plat transcripts were determined by semi-quantitative RT-PCR as described previously (Svoboda et al. 2000). The amount of the nontargeted Plat PCR product permits relative comparison of microinjected samples (Svoboda et al. 2000). (B) EGFP dsRNA induces degradation of the chimeric transcript. Relative amounts of the chimeric transcript in microinjected oocytes were estimated based on co-injection of rabbit globin mRNA (10 ng/μL). High amounts (∼7.5 × 10⁶ molecules) of microinjected chimeric message do not allow detection of degradation of the chimeric mRNA (left panels), whereas dramatic reduction (right panels) of chimeric mRNA is observed in oocytes microinjected with lower amounts (∼10⁴ molecules).