Superfund Research Program

Biomarkers of Exposure Using Accelerator Mass Spectrometry

Project Leader: Kenneth W. Turteltaub (Lawrence Livermore National Laboratory)
Grant Number: P42ES004705
Funding Period: 1995 - 2006

Project-Specific Links

Final Progress Reports

Year:   2005 

The goal of this project is to develop and validate a method to quantitate chemical modification of DNA and proteins in animals and humans by environmental toxicants such as benzene, trichloroethylene (TCE) and heterocylic amines (HA). In particular, Dr. Henderson and his research team want to understand the relationship between age, gender, species and levels of adducted biomolecules from exposures to toxic chemicals at concentrations present at Superfund sites (as opposed to the normally high concentrations of such compounds used with in vivo laboratory studies). In order to accomplish these goals, it is desirable to label damaged biomolecules with a radioactive compound to enable the detection of very low yet biologically relevant concentrations of DNA or protein damage. In particular, the team aims to label sites if DNA damage with a radiocarbon label in order to facilitate detection of the damage with a sensitive and precise technology called accelerator mass spectrometry (AMS). This year they established that an enzyme called polynucleotidyl terminal transferase (TnT) can efficiently label DNA that contains HA modifications at the ends or termini of the molecule. In order to generate HA-modified DNA termini, another type of enzyme called a nuclease must be used to digest long strands of DNA that has been exposed to HAs. The nuclease must stop at the sites of HA modified nucleotides in the DNA in order to liberate a sites for TnT-mediated to labeling. Currently, the team is developing nuclease digest conditions necessary for the final steps of the assay development, which will enable use of the AMS assay on biological samples.