FIG. 8.

Effects of VEEV or SINV infection upon IFN-β gene and ISG transcription in IFN-posttreated neurons. Neuron cultures were either mock infected (M) or infected with VEEV or SINV as described in Materials and Methods and then either left untreated or treated with 1,000 IU/ml of IFN-α/β for 6 h beginning at 6 (6 + 6) or 12 (12 + 6) h p.i. Treatment and harvest times were set to allow gene upregulation and minimize cytopathic effects of viruses upon untreated cells. Total cellular RNA was harvested 6 h after the onset of IFN treatment and processed for semiquantitative RT-PCR for the indicated mRNAs as described in Materials and Methods.