Modulation of HIV-1 replication by miRNA. HIV-1 impacts the cellular miRNA pathways in several ways. The figure shows a schematic representation of the HIV-1 provirus with the indicated viral genes and LTRs, including the transcription start site in the 3’LTR. PCAF and Cyclin T1, which are both essential cofactors for viral transcription, are targeted by the indicated miRNAs in resting T cells and monocytes. A cluster of miRNAs is targeted directly towards the 5'end of the HIV-1 genome and their inhibition rescues infectious virus from resting T cells. Finally two sets of miRNA that are derived from the HIV-1 genome are shown. Their location within the LTR (TAR and nef) is duplicated (arrows).