Bioengineering Seminar Series

"CRISPR and DNA Repair"

Taekjip Ha, Ph.D.
Bloomberg Distinguished Professor of Biophysics and Biophysical Chemistry, Biophysics, Biomedical Engineering
Department of Biophysics and Biophysical Chemistry
Johns Hopkins University School of Medicine
Howard Hughes Medical Institute

Double strand breaks (DSB) are frequently generated, and researchers have discovered many proteins and processes needed to repair the breaks. However, relative timing of sub-stages of DNA repair or even their ordering has been difficult to determine due to the lack of method to synchronize the generation of well-defined breaks in living cells. Exposing cells to X-ray and UV can produce massive DNA damages at a defined time point, but the nature of the damage is ill-defined, and damages are made randomly. CRISPR-Cas systems allow the generation of breaks at specifically defined genome locations, but despite many attempts to develop ligand- or light-inducible CRISPR-Cas systems, the cleavage kinetics remains slow, leading to unsynchronized repair. We developed a very fast CRISPR-Cas9 can generate a DNA break at a defined locus at a well-define (within seconds) time point, allowing us to reveal the mechanisms of break recognition and study DSB repair and other cellular processes with an unprecedented spatiotemporal control. 

Taekjip Ha is a Bloomberg Distinguished Professor of Biophysics and Biophysical Chemistry, Biophysics, and Biomedical Engineering at Johns Hopkins University School of Medicine. He is also an investigator with the Howard Hughes Medical Institute. He uses sophisticated physical techniques to manipulate and visualize the movements of single molecules to understand basic biological processes involving DNA and other molecules. His study is focused on pushing the limits of single-molecule detection methods to study protein–nucleic acid and protein-protein complexes and the mechanical basis of their interactions and functions – both in vitro and in vivo – that are important for genome maintenance.

Ha received his undergraduate degree in Physics, from Seoul National University, Seoul, Republic of Korea in 1990. He earned his Ph.D. In Physics from the University of Berkeley in 1996. After postdoctoral training at Stanford University, he was a Physics professor at University of Illinois at Urbana-Champaign for fifteen years until 2015.

Ha serves as a member of Editorial Boards for Science, Cell, eLife, PRX, Structure, PCCP, Physical Biology and Cancer Convergence. He is a member of the National Academy of Science and an elected fellow of the American Academy of Arts and Sciences.

The Bioengineering Seminar Series is co-hosted by the Institute for Bioengineering and Bioscience and the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, and they are open to all in the bio-community.