Journal of Biotechnology & Biomaterials
Open Access

Abstract

Human SAMHD1 possesses dual enzymatic functions. It acts as both a dGTP-dependent triphosphohydrolase and as an exoribonuclease. The dNTPase function depletes the cellular dNTP pool which is required for retroviral reverse transcription in differentiated myeloid cells and resting CD4+ T cells; thus this activity mainly plays a role in SAMHD1- mediated retroviral restriction. However, a recent study demonstrated that SAMHD1 directly targets HIV-1 genomic RNA via its RNase activity and that this function (rather than dNTPase activity) is sufficient for HIV-1 restriction. While HIV-1 genomic RNA is a potent target for SAMHD1 during viral infection, the specificity of SAMHD1-mediated RNase activity during infection by other viruses is unclear. The results of the present study showed that SAMHD1 specifically degrades retroviral genomic RNA in monocyte-derived macrophage-like cells. Consistent with this, SAMHD1 selectively restricted retroviral replication but did not affect the replication of other common non-retro RNA genome viruses suggesting that the RNase mediated antiviral function of SAMHD1 is limited to retroviruses. In addition, neither inhibiting reverse transcription by treatment with several reverse transcriptase inhibitors nor infection with reverse transcriptase-defective HIV-1 altered RNA levels after viral challenge indicating that the retrovirus-specific RNase function is not dependent on processes associated with retroviral reverse transcription.

Biography

Email: ksahn@snu.ac.kr