FIG. 5.

Northern blot and RT-PCR analyses of Oas1a and Oas1b gene transcripts during WN virus infection and following priming with IFN-α/β and pIC. (A) Total cellular RNA (4 μg) from noninfected, nonadherent macrophages (N) (one lane); noninfected, adherent macrophages (A) (two lanes); and WN virus-infected macrophages at days 3 (3d) (two lanes) and 5 (5d) (two lanes) p.i. was separated on a 1.2% agarose denaturing gel in the presence of 2.2 M formaldehyde. After capillary transfer to Hybond NX membrane, the blot was hybridized to ³²P-labeled cDNA probes for either Oas1a or Oas1b genes, respectively. The same blot was reused after stringent stripping of the probe and testing for the absence of remaining activity by extended autoradiography. The cells isolated from susceptible He and resistant RV mice were either infected (WN) or not infected (Con) with WN virus. (B) Effects of priming with 100 IU of IFN-α/β for 24 h or with 1 μg of pIC/ml for 1 h on Oas1a and Oas1b gene induction prior to WN virus infection. Total cell RNA from two parallel replica samples (10⁶ cells each) was isolated 24 h posttreatment and used in RT-PCR. Reaction products were analyzed by agarose gel electrophoresis. The total cellular RNA was also analyzed by agarose gel electrophoresis, and the amount of 28S rRNA was used as an internal control.