FIG. 4.

Dimerization level of viral RNA isolated from BH10 (lane 1), GGCG (lane 2), UUAA (lane 3), and Δ248–256 (lane 4) viruses containing 1.3 × 10¹², 5 × 10¹², 5 × 10¹², and 4 × 10¹² CAp24 copies. GGCG viruses have a C258G transversion. UUAA viruses have CGCG261 replaced by UUAA. Lane 5, dimerization level of viral RNA isolated from BH10 viruses containing 4 × 10¹² CAp24 copies. Electrophoresis was for 4 h 35 min in 1% agarose. The autoradiographic exposure was for 1 h. Scanning of lanes 1 to 3 and equivalent lanes from other Northern blots indicates that GGCG, UUAA, and Δ248–256 viruses, respectively, package genomic RNA 0.78 ± 0.12, 1.1 ± 0.11, and 0.4 ± 0.06 as well as BH10 viruses. These numbers are consistent with previous estimates using dot blot assays (18).