FIG. 2.

Presence of two distinct types of viral RNAs, with one of these associated with RNA polymerase activity. Crude lysates of oocysts were fractionated by sucrose gradient centrifugation, and the fractions were analyzed for the presence of viral RNA and RNA polymerase activity. (A) Ethidium bromide-stained 0.8% agarose gel with nucleic acids purified from even fractions of gradient. (B) Northern blot analysis, where nucleic acids were extracted from fractions and separated on agarose gels under nondenaturing conditions, then denatured in situ, and transferred to the filter. Hybridization was performed with ³²P-labeled riboprobes complementary to the plus strand of the L-dsRNA. A similar pattern of hybridization was observed with riboprobes complementary to the plus strand of the S-dsRNA (data not shown). In experiments with ³²P-labeled riboprobes complementary to the minus strands of the L- and S-dsRNAs, hybridization occurred only with RI and dsRNA (data not shown). (C) Autoradiogram of ³²P-labeled products of RNA polymerase assay resolved by electrophoresis on an 0.8% agarose gel.