FIG. 3.

Specific binding of M protein to replicating DI RNAs containing the packaging signal in MHV-infected cells. Cell lysates were prepared from DI RNA-transfected, MHV-infected cells at 12 h p.i. Anti-N protein monoclonal antibody (anti-N) and anti-M protein monoclonal antibody (anti-M) were independently added to equal volumes of cell lysates, and immunoprecipitation was performed. RNA was extracted from the immunoprecipitated samples. Intracellular (i.c.) RNAs and virion RNAs were extracted as described in the legend to Fig. 2. Extracted RNAs were analyzed on Northern blots using a probe that binds to DI RNAs. Only the section of the autoradiogram with the DI RNAs is shown. Each panel shows representative data from triplicate experiments.