FIG. 3.

RNA-protein complexes formed by open cores and VP6-open cores. (A) ³²P-labeled SP72-v3′40 (7.5 pmol, 0.17 μg) was incubated alone or with open cores or VP6-open cores, each containing 3.3 μg of VP2, or with 2 μg of VP6 eluted from double-shelled particles with CaCl₂. Some reaction mixtures also included luciferase RNA (1.7 pmol, 1.0 μg). (B) ³²P-labeled SP72-v3′40 (7.5 pmol, 0.17 μg) was incubated alone (lane 1) or with VP6-open cores containing 3.3 μg of VP2 in the absence of competitor RNA for 60 min (lane 2) or 30 min (lane 3) or in the presence of 1.7 μg of luciferase RNA for 60 min (lane 5). Lane 4 shows complexes formed when ³²P-labeled SP72-v3′40 was preincubated with the VP6-open cores for 30 min and then, after addition of 1.7 μg of luciferase RNA, the incubation was continued for another 30 min. Probe-protein complexes were detected by electrophoresis on 8% polyacrylamide gels and by autoradiography. ori, origin.