FOS and infection: Knockdown of Fos in LMH cells significantly decreased the transcription of both the IE gene ICP4 and the E gene ICP27 at 12 h post infection (hpi), as determined by qRT-PCR (Figure 2B), while no significant effect of Jun on the transcription of either viral gene was observed, suggesting that Fos but not Jun plays a regulatory role in the ILTV gene transcription.