The content in this collection is available only to Washington University in St. Louis users per the request of the Office of Undergraduate Research. If you have questions, please contact .

Document Type

Feature Article

Publication Date

Fall 9-1-2011

Publication Title

Washington University Undergraduate Research Digest: WUURD 7(1)


Peer Editors: Jordan Weiner and Sarah Cohen; Faculty Mentor; Zhongsheng You

Double-strand breaks (DSBs) are one of the most severe forms of DNA damage, capable of causing severe genomic instability if unrepaired or repaired inappropriately. To repair such damage, cells mainly use either homologous recombination (HR) or non-homologous recombination end joining (NHEJ). The choice of repair mechanism is in part regulated by DNA resection, which generates 3’ single-strand tails that enable HR to proceed. While the mechanism of DNA resection is well-understood, little is known about its regulation. To shed light on this realm, we studied the behavior of a major protein in the mechanism called endonuclease 1 (Exo1). More specifically, we asked: Which parts of Exo1 are important for translocating it to DSB sites, where it can perform its function? To tackle this question, various Exo1 truncations fused to green fluorescent protein (GFP) were generated and transfected into human cells. A “laser-scissors” technique was used to create defined DSBs and microscopy was used to monitor the kinetics and dynamics of Exo1 translocation. Results revealed three domains within the protein, two of which promote Exo1 association with DSBs and one of which inhibits such association. After identifying the regulatory domains, we aim to study the molecular basis of such regulation, continuing the research on genome stability maintenance.

From the Washington University Undergraduate Research Digest: WUURD, Volume 7, Issue 1, Fall 2011. Published by the Office of Undergraduate Research, Joy Zalis Kiefer Director of Undergraduate Research and Assistant Dean in the College of Arts & Sciences; Kristin Sobotka, Editor.


Copyright: All work is copyrighted by the authors and permission to use this work must be granted. The Office of Undergraduate Research can assist in contacting an author.

Off-campus Download