HIV is a retrovirus, which means it carries single-stranded RNA has its genetic material rather than the double-stranded DNA that human cells carry. Retroviruses also have the enzyme reverse transcriptase, which enable it to copy RNA into DNA and use that DNA “copy” to infect human, or host, cells.
When HIV infects a cell, it first attaches to and fuses with the host cell. Then the viral RNA is converted into DNA and the virus uses the host cell’s machinery to replicate itself during a process called reverse transcription. The new copies of HIV then leave the host cell and move on to infect other cells.
Uncovering step by step through details of the mechanism of HIV entry has profound implications for viral tropism, transmission, pathogenesis, and therapeutic intervention.
Now, researchers at the National Institutes of Health have discovered a key step in the process that HIV uses to inject its genetic material into cells.
In a study appearing in Cell Host & Microbe, led by Leonid V. Chernomordik, Ph.D., at NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), the team of researchers has revealed how blocking this key step in the process chemically can
prevent HIV genetic material from entering cells.The findings could lead to the eventual development of new drugs to prevent HIV infection.
The process, wherein the protein on the surface of HIV binds to molecules on the cell’s surface, was seen to activate a protein called TMEM 16F that transfers another molecule inside the cell membrane, phosphatidylserine, to the membrane’s outer surface.
The researchers believe molecules in the viral membrane bind with the exposed phosphatidylserine on the cell surface to enhance the virus’ fusion to the cell. They found that blocking the transfer of phosphatidylserine to the cell surface—or attaching another molecule to phosphatidylserine so it can’t bind with HIV—prevents the virus from infecting the cell.
Therefore, scientists believe in this theory that developing drugs capable of blocking each of these steps could provide the basis for treatments to prevent HIV from infecting cells. But it is still too early to say for sure and definitely needs much more research.
