Fig 5.

RNA packaging phenotype of the silPS mutant. (A) Outline of the procedures for purification, normalization, and analysis of silPS and wild-type virions, as detailed in Materials and Methods. Infectious titers were determined by plaque assay on L2 cells at 37°C; chemiluminescence values are given in arbitrary volume units, as measured with a Bio-Rad ChemiDoc XRS+ instrument. (B) Western blot of normalized amounts of immunopurified wild-type and silPS virions probed with anti-N monoclonal antibody J.3.3 and anti-M monoclonal antibody J.1.3. (C) Coomassie blue-stained SDS-polyacrylamide gel of normalized amounts of immunopurified wild-type and silPS virions; samples on the right are a 5-fold dilution of those on the left. Molecular mass standards are indicated on the left of each panel (B and C). (D) Northern blot of total RNA isolated from infected 17Cl1 cells, from which wild-type or silPS virions were purified, or from mock-infected cells. (E) Northern blot of RNA isolated from normalized amounts of immunopurified wild-type and silPS virions. MHV RNA was detected with a probe specific for the 3′ end of the genome (D and E).