In the IRMA teleconference held on March 15th, 2012, Dr. Ian McGowan explained, the effects of 1% tenofovir gel on gene expression and regulation (click here for his slides). There were many questions on the call about gene expression and gene regulation, and because I studied Molecular and Cellular Biology at the University of Illinois Urbana –Champaign, I thought I would try to explain what it means as simply as possible. After all, many advocates are hearing about gene expression for the first time! So, gene expression occurs when the genetic information, which is provided by our DNA, is converted to RNA. The RNA is then converted to many different proteins by a process called translation. The proteins that are produced are needed for the functionality of the cell.

Our DNA is filled with genetic code that gives cells instructions on what protein to produce and when to produce it. Certain proteins need to be regulated or used at precise times. Cells can signal the regulators to control production of a protein. When the cell is lacking the need of a specific protein it will signal the gene to make more of the protein, this is called up-regulation. However, if there is too much of a protein, or a protein is not needed anymore the cell is signaled to slow down or stop the production of a certain protein. This is called down-regulation.

In the case of tenofovir gel, the gene sequencing tables show that the gel is causing the cells to down regulate, or turn off the genes from producing proteins after seven days of use. The reaction that is observed when the drug is applied better maps out protein and cellular behavior pathways. The findings observed in the MTN 007 trials show that the behavior of the cell when used with tenofovir causes the amount of proteins in the cell to decrease. For a further tutorial on the details of the science of gene expression or regulation, click here. Or email me at nthakkar@aidschicago.org