Figure 1.

HIV-1 infection and intrinsic immune response in SAMHD1-deficient mouse cells. Intracellular dNTP concentrations are significantly increased in multiple cell types from samhd1-null mouse cells compared with control cells, indicating that mSAMHD1 acts as a dNTP hydrolase in vivo to reduce the intracellular dNTP pool. Spontaneous transcriptional induction of type I IFN-stimulated genes (ISGs) has been observed in several cell types and tissues from samhd1-null mice compared with wild-type mice. Therefore, mSAMHD1 might play a role in regulating the IFN signaling pathway in vivo, although the innate sensor that triggers the spontaneous ISG responses is unclear. Transduction of SAMHD1-deficient mice or derived cells with HIV-1 vectors is increased relative to wild-type mice or murine cells, which appears to be dependent on the affinity for dNTPs of the HIV-1 RT and the experimental conditions in these studies (refer to Table  1). RT, HIV-1 reverse transcriptase.