APOBEC3G and HIV infectious disease: Several restriction factors have been identified that inhibit human immunodeficiency virus (HIV) infection, including APOBEC3G [2], BST2/tetherin and SAMHD1 [3], which block discrete steps of viral replication, such as reverse transcription (APOBEC3G and SAMHD1) or the release of progeny particles from infected cells (tetherin).