Patrick Sung, DPhil

Research Scientist

Research Interests

Biochemistry; Biophysics; DNA Repair; Radiation Oncology; Homologous Recombination; DNA End-Joining Repair

Research Organizations

Molecular Biophysics and Biochemistry: Sung Lab

School of Public Health

Therapeutic Radiology: Radiobiology

Radiobiology & Radiotherapy

Yale Cancer Center: Radiobiology & Radiotherapy

Office of Cooperative Research

Research Summary

Endogenous free radicals and environmental agents such as ionizing radiation induce DNA double-strand breaks. The repair of these breaks is crucial for the maintenance of genome stability. Two distinct pathways help eliminate DNA double-strand breaks. In homologous recombination, the repair of a broken DNA molecule requires an intact homologous duplex to direct the process. Alternatively, a pathway known as non-homologous DNA end joining (NHEJ) simply rejoins the ends of the broken DNA molecule. Our research efforts focus on delineating the mechanisms of homologous recombination.

The recombinational repair of DNA double-strand breaks is mediated by a group of genes called the RAD52 epistasis group. In mammals, the efficiency of recombinational DNA repair is modulated by the tumor suppressors BRCA1, BARD1, BRCA2, PALB2, and BLM, providing compelling evidence that this repair pathway functions to suppress cancer formation. Importantly, recombinational DNA repair is also required for the removal of interstrand DNA crosslinks induced by bifunctional crosslinking agents, which are commonly used to treat various malignancies. In 1994, we identified the yeast Rad51 protein, a key member of the RAD52 group, as the recombinase that mediates the “homologous DNA pairing and strand exchange “reaction central to all recombination-dependent processes, including the repair of DNA double-strand breaks. This finding marked the beginning of studies on recombination enzymology in eukaryotic organisms and has created a much-needed experimental framework for dissecting the role of the other RAD52 group members in the recombination reaction.

Specialized Terms: Repair of DNA double-strand breaks; Repair by homologous recombination; Repair by DNA end-joining

Selected Publications

  • BRCA1-BARD1 promotes RAD51-mediated homologous DNA pairing

    Zhao W, Steinfeld JB, Liang F, Chen X, Maranon DG, Jian Ma C, Kwon Y, Rao T, Wang W, Sheng C, Song X, Deng Y, Jimenez-Sainz J, Lu L, Jensen RB, Xiong Y, Kupfer GM, Wiese C, Greene EC, Sung P. Nature. 2017 Oct 19;550(7676):360-365.

Full List of PubMed Publications

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Contact Info

Patrick Sung, DPhil
Mailing Address
PO Box 208024
333 Cedar Street

New Haven, CT 06520-8024

Sung Lab