Final answer:
HIV uses the enzyme integrase to insert the DNA copy of its RNA into a cell's chromosome during infection. Reverse transcriptase is involved in converting RNA into DNA before integration.
Step-by-step explanation:
The protein that the HIV virus uses to insert the DNA copy of its RNA into the chromosome of a cell is known as integrase. This enzyme is responsible for the integration of viral DNA into the host cell's genome. During the process of infection, HIV binds to the CD4 receptor of an immune cell, and after fusion with the cell membrane, its contents, including RNA and enzymes like reverse transcriptase, are released. Reverse transcriptase converts the viral RNA into DNA, which is then incorporated into the host's genome with the help of integrase. As part of the HIV lifecycle, once the viral DNA is integrated, it can either remain dormant or be activated to produce new viruses.