SAMHD1 and cytomegalovirus infection: Unlike HPV16, the effects of beta-herpesvirus human cytomegalovirus (HCMV) on SAMHD1 protein expression appear to be cell specific: While HCMV infection of THP-1 cells induces SAMHD1 expression in a mechanism independent of viral gene expression [177], protein levels decrease in HCMV+ MDMs through transcriptional repression and proteasome-dependent mechanisms [178].