Cellular factors involved in HIV-1 RNA transport

HIV-1 assembly and genomic RNA encapsidation have been intensively studied for many years. Many details of the interaction between the RNA packaging signal and the nucleocapsid (NC) domain of the structural Gag protein are now understood. However, there are still many unknowns regarding the spatial and temporal control of the RNA packaging process. It is generally assumed that cellular mRNAs are complexed with RNA-binding proteins during or shortly after transcription. These ribonucleoprotein complexes (RNPs) are subsequently trafficked out of the nucleus into the cytoplasm, where they can be translated at various locations, stored in stress granules during stress responses or destroyed by various RNA degradation machineries. It is assumed that the HIV-1 genomic RNA (gRNA) is also subject to these processes. The composition of the genomic RNP may thus determine the fate of the viral RNA. Indeed, it has been shown that altering the expression level of certain host proteins can affect HIV-1 translation, gRNA localization or particle assembly, implying that these proteins are important for efficient viral replication. Consequently, there is an increasing interest in targeting these host factors as an additional approach to antiviral treatment.