MISSION: Our laboratory works at the interface between the fields of DNA Damage & Repair and Telomere Biology. Telomeres cap chromosome ends and profoundly influence genome stability, life span and human health. When chromosomes lose their telomere caps the cells can no longer divide, causing loss of regenerative capacity which drives degenerative diseases during aging. If telomeric caps are lost in pre-cancerous cells then this causes genetic alterations that hasten the progression to cancer. Telomeres shorten with age, but genetic and environmental factors can accelerate telomere loss. We want to understand how DNA damage at telomeres impacts their function, and whether or how the damage is repaired. The long term goals of our research are to develop novel strategies that preserve telomeres in healthy cells and delay aging-related diseases including cancer, or that conversely target telomeres in cancer cells to stop their proliferation.
Research projects in the lab include:
1. Determining how DNA damage induces alterations in telomere length and integrity.
We are particularly interested in telomeric DNA damage caused by oxidative stress and sunlight exposure.
2. Elucidating how telomere binding proteins (termed shelterin) regulate the activity of DNA repair enzymes.
Current focus is on base excision repair and nucleotide excision repair pathways.
3. Defining how DNA damage impacts telomerase activity; the enzyme that lengthens telomeres.
4. Developing new tools and technologies for visualizing telomeres and for selectively damaging telomeres.
5. Determining how damage to telomeres influences mitochondrial function and vice versa.
APPROACH: We use cutting edge complementary biochemical, biophysical and cellular approaches in collaboration with numerous laboratories at the University of Pittsburgh, Carnegie Mellon University and outside universities and research institutes. Examples of some of our approaches are shown below.
To examine telomere structure and integrity we prepare metaphase chromosome spreads from cultured human cells and stain telomeres with fluorescent peptide nucleic acid probes.We are working with labs at the Center for Nucleic Acids Science and Technology (CNAST) at Carnegie Mellon University (see links) to develop more sensitive probes for staining critically short telomeres. We perform fixed and live cell microscopy to examine the recruitment of DNA repair enzymes to telomeric ends. We have a Nikon Ti-E Perfect Focus Live Cell Imaging System in the lab and access to cutting edge high resolution microscopes at the Center for Biological Imaging (see links).
We also study purified components of DNA repair machineries, telomeric shelterin proteins and telomerase to determine how interaction among these proteins impacts their activities. We are also investigating how DNA damage and oxidative DNA lesions influence the ability to telomerase to lengthen telomeric DNA, and the ability of telomeric shelterin proteins to bind and protect the telomeres. The lab houses a 2016 AKTA Pure FPLC system for protein purification. We are collaborating with a number of biophysics laboratories to conduct single molecule studies with the purified proteins to further advance our understanding.