Fig. 1.

ZAP promotes target viral mRNA degradation in the cytoplasm. Rat2-HAZ and Rat2-NZAP-Zeo cells were infected with MLV-luc virus. Forty-eight hours after infection, actinomycin D was added to the media at a final concentration of 5 μg/ml to stop transcription. (Upper) At the indicated time points, the cells were lysed and the cytoplasmic RNA was extracted and subjected to Northern blotting. (Lower) The relative levels of the viral mRNA were measured by using a phosphorimager and were normalized by the GAPDH mRNA level.