Viral gene expression is required for sustained SINE expression.

(A) Temporal progression of the MHV68 productive replication cycle. Upon MHV68 infection, the virus enters cells and the dsDNA viral genome is delivered to the nucleus. The viral gene expression program commences with transcription of immediate early (IE) genes, which in turn activate transcription of early (E) genes. This is followed by viral DNA synthesis, which activates transcription of late (L) viral genes, and culminates in infectious progeny virus production. The point at which different treatments (UV-irradiated virus, or PAA) arrest the viral life cycle is shown. (B) RNA isolated from NIH3T3 cells incubated with mock- or U.V.-treated MHV68 at the indicated time points was subjected to RT-qPCR for the indicated viral genes to demonstrate that UV treatment prevents viral gene expression. (C) RNA described in (B) was used to monitor the levels of B1, B2, and 7SK RNA by primer extension. (D) NIH3T3 cells were infected with MHV68 at an MOI of 5 in the presence of 200 μg/mL of PAA. 24 hpi total RNA was used to monitor by RT-qPCR the expression of ORF65, a viral late gene whose transcription is dependent on viral DNA replication. (E) RNA described in (D) was used to monitor the levels of B1, B2, and 7SK RNA by primer extension.