FIGURE 2.

Inhibition of EMCV replication by poly(A) tail deficiency in nuclease-treated Krebs-2 S10 extract. (A) Translation efficiencies of poly(A+) and poly(A−) EMCV RNA. The translation of the indicated concentrations of the intact and deadenylated EMCV RNA was carried out as described for Fig. 1B with the exception that nuclease-treated extract was used. Samples were analyzed by SDS-PAGE and fluorography. The positions of EMCV-specific proteins are indicated on the right. Products of translation of endogenous cellular mRNA were undetectable (data not shown). (B) Poly(A+) and poly(A−) EMCV RNA dose responses of RNA synthesis. The indicated concentrations of poly(A+) and poly(A−) EMCV RNA were added to the reaction mixtures containing nuclease-treated extract. The products of RNA synthesis were labeled with [α-³²P]CTP and analyzed as described for Fig. 1D. (Arrow) Position of single-stranded EMCV RNA. (C) Poly(A+) and poly(A−) EMCV RNA dose responses of virus yield. Reaction mixtures containing nuclease-treated extract were programmed with the indicated concentrations of poly(A+) or poly(A−) EMCV RNAs for 18 h at 32°C, treated with RNase A/T1, and assayed for infectivity. The data are averages (with standard deviation from the mean) of three independent titer determinations.