Human DNA Polymerase Gamma for Testing the Effect of Drugs on Mitochondrial Function

One of the primary means for treating HIV infection is the use of antiviral nucleotide or nucleoside analogs. These analogs work by inhibiting the activity of reverse transcriptase, the enzyme responsible for preparing the HIV genome for integration into the DNA of the host cell. Although these analogs do not have an effect on the polymerases responsible for replicating the human genome, the polymerase responsible for replicating the mitochondrial genome is sensitive to these analogs. When patients are exposed to nucleotide or nucleoside analogs through long-term treatment regimens, the replication of the mitochondrial genome can be adversely affected. Since mitochondrial functionality is necessary for cell activity, the nucleotide and nucleoside analogs can cause serious and unwanted side-effects.

This invention concerns the cloning and purification of DNA polymerase gamma, the polymerase responsible for replicating the mitochondrial genome. The enzymes that have been purified include the wild-type version, a version which lacks exonuclease (proofreading) activity, and several versions with modified activity due to the mutation of the enzyme. These purified enzymes can be used to directly test the effects of new drugs that affect the activity of polymerases, such as nucleotide and nucleoside analogs.

Potential Commercial Applications: Competitive Advantages:
  • Research reagent to screen the effects of antiviral drugs (nucleotide and nucleoside analogs) on mitochondrial function
  • Research reagent to test the mitochondrial toxicity of other drugs that can affect polymerase activity
  • Purified polymerase allows for direct analysis of the effect of nucleotide analogs on DNA polymerase gamma
  • Different formats of the enzyme such as the exonuclease-deficient version, allows comprehensive testing of drug candidates

Development Stage:
In vitro data available


William Copeland (NIEHS)  ➽ more inventions...

Susan Lim (NIEHS)  ➽ more inventions...

Rajesh Kasiviswanathan (NIEHS)  ➽ more inventions...

Intellectual Property:
HHS Reference Nos. E-191-2011/0, B-035-1998/0, B-035-1998/1 - Research Materials. Patent protection is not being pursued for these technologies.

Longley MJ, et al. PMID 9671525

Collaboration Opportunity:

The NIEHS is seeking statements of capability or interest from parties interested in collaborative research to further develop, evaluate or commercialize DNA polymerase G and method of purifying. For collaboration opportunities, please contact Sally E. Tilotta, Ph.D. at

Licensing Contact:
Vidita Choudhry, Ph.D.
Phone: 301-594-4095

OTT Reference No: B-035-1998-0
Updated: May 7, 2018