Repair Machinery for Radiation-Induced DNA Damage
Abstract
Understanding the DNA repair mechanisms for ionizing radiation (IR)-induced DNA damage and having prior knowledge of a patient's lR-specific repair capacity will help to determine how patients will respond to radiation therapy and to design more effective treatments. Our prior objective to construct a mutant cell line for the APEl nuclease gene was not met despite numerous experiments and multiple approaches. Therefore, we initiated two new objectives dealing with other enzymatic cellular components that are essential for IR damage recognition and repair. First, we evaluated the new technology of siRNA knockdown of gene expression for both APEl and polynucleotide kinase (PNK), a protein that plays a major role in processing the termini of DNA breaks. The APEl experiments were unsuccessful, for unknown reasons, but experiments with PNK look promising based prior experience with human tumor cells. Second and most important, we have shown that we can use immuno-fluorescence to detect the sites of doublestrand breaks (DSBs) caused by IR in immortalized normal human fibroblasts. The assay is extremely sensitive, with low background, and is linear with dose from 0 to 90 cGy. This immuno-detection system has as wide application to studying the mechanisms of DSB repair and - will be used extensively in future studies.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 2003
- Accession Number
- ADA423482
Entities
People
- Lawrence H. Thompson
Organizations
- Lawrence Livermore National Laboratory