SAMHD1 and HIV-1 infection: Using a well-established assay to quantify the levels of distinct viral DNA forms during HIV-1 infection, the authors observed that SAMHD1 exhibited enhanced efficacy in inhibiting the 2-long terminal repeat (LTR) form of HIV-1 DNA (a crucial indicator of nuclear entry of HIV-1 cDNA) compared to suppressing the synthesis of HIV-1 cDNA in nondividing immortalized cell lines, suggesting an additional suppressive effect on HIV-1 DNA nuclear transport by SAMHD1.