RRM2 and infection: The majority of cell cycle gene transcripts, including RRM2, MYBL2, CDK1, and TK1, remained significantly elevated at early set-point viral load time points, as did BIRC5. At the chronic stage of infection the majority of cell cycle gene transcripts returned to pre-infection levels, except for RRM2, which remained just 2.8-fold higher, while BIRC5 expression returned to pre-infection levels.