CUL1 and cytomegalovirus infection: This result did not indicate a direct role of CUL2 or CUL1 in SAMHD1 loss during HCMV infection since siCUL1 and siCUL2 transfection increased SAMHD1 level in normal HF cells and these also reduced viral late gene expression, which might be required for SAMHD1 loss (Figures 7C,D).