FIG. 6.

Association of transcriptase and replicase activities with fractions of CsCl gradients. (A and B) ³²P-labeled products from pulse (A) and pulse-chase (B) RNA polymerase assays resolved by electrophoresis on 0.8% agarose and exposed to X-ray film. (C) Effect of RNase on products of RNA polymerase reactions from fractions 10 and 14. Purified products were treated with RNase A (10 μg/ml, for 30 min at 37°C) in the absence (−) or presence (+) of 0.6 M NaCl. After treatment, RNA was separated on an 0.8% agarose gel and detected by autoradiography. (D) Identification of the polarity of the RNA polymerase products from fractions 10 and 14. Unlabeled transcripts corresponding to minus and plus strands of the L-dsRNA (L) and S-dsRNA (S) were synthesized on cDNA clones using T7 and T3 RNA polymerases. Usually, two bands were identified by ethidium bromide staining of the products of the reaction, as was observed previously (18). Then unlabeled products were electrophoresed on 1.2% agarose, transferred to filters, and probed with ³²P-labeled products of polymerase reactions synthesized by fractions 10 and 14.