Replication
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The cycle begins at the top of the drawing with HIV binding to a specific cell-membrane receptor, CD4. CD4 receptors are found not only on helper T-cells, but also on monocyte/macrophages and microglial cells. The virus uncoats once inside the cell, and reverse transcriptase begins to form double-stranded DNA from the RNA core. At the end of the transcribed DNA are long-terminal repeats (LTR), which allow the viral DNA to insert itself into the host genome. From the proviral DNA, now part of the host, mRNA can be transcribed at any time, with capsids being assembled in the cell cytoplasm. The virus buds from the host cell membrane, acquiring part of the host cell membrane as its protective coat.