News | O'Brien Lab

May 2026

David Beier successfully defended his doctoral dissertation on May 21. Congratulations Dr. Beier!

Welcome to Grishmasri Taminidi, an undergraduate student from Michigan State University who is doing research in the lab while participating in the U-M Medical School's Cancer Research Summer Internship Program (CaRSIP).

Congratulations to Jamie Cronk, who graduated from the University of Michigan with a BS degree in Biochemistry. Jamie will begin her medical training this summer at AT Still University School of Osteopathic Medicine in Arizona.

April 2026

Jacob Firby received his MS degree after presenting his research at the 2026 MS Program in Biological Chemistry Symposium and submitting his thesis, "Developing Inhibitors for Activation-Induced Cytidine Deaminase." Congratulations Jake!

David Beier's paper, "Fidelity of DNA Ligase I is sensitive to physiological Mg²⁺ level," is in press at JBC and available online. Co-authors with David and Pat are collaborators Eunhye Lee (MGH, Harvard), Ihn Sik Seong (MGH, Harvard), and Vanessa Wheeler (MGH, Harvard, Broad Institute).

March 2026

PhD student David Beier gave a talk entitled "Enhanced DNA repair fidelity of the K845N LIG1 allele and its potential in delaying Huntington's Disease onset" at the Frontiers in Nucleic Acid Biochemistry session of the 2026 ASBMB annual meeting.

"Huntington’s disease LIG1 modifier variant increases ligase fidelity and suppresses somatic CAG repeat expansion" has been published in PNAS and is available online. Researchers in the O'Brien lab and the labs of Vanessa Wheeler (MGH, Harvard, Broad Institute) and Ihn Sik Seong (MGH, Harvard) investigated a missense variant in DNA Ligase 1 (K845N) that is associated with a profound delay in the onset of Huntington’s disease (HD). Using in vitro ligase assays, human cell-based studies, and a mouse model of HD, they discovered that K845N ligase enhances substrate discrimination against mismatched substrates, thus increasing DNA repair fidelity, conferring protection against oxidative stress and slowing somatic expansion of the HD CAG repeat. Their results provide a mechanistic foundation for considering DNA ligase fidelity as a therapeutic target in HD and potentially in other trinucleotide repeat disorders. PhD student David Beier shares first authorship of the paper with Eunhye Lee from the Seong lab and Wonju Kim from the Wheeler lab.

December 2025

Happy holidays from the O'Brien lab!

October 2025

Welcome to PIBS PhD students Bella Castellano-Moen and Abbey Hanes, who are doing fall research rotations in the O'Brien lab. Abbey graduated from the State University of New York College at Geneseo with a BS degree in Biochemistry, and Bella graduated from the University of Wisconsin–Madison with a BS degree in Molecular Biology.

September 2025

David Beier won a prize for his poster, "Fidelity of DNA ligase I is tuned by magnesium ion concentration," at the 2025 Midwest Enzyme Chemistry Conference at the University of Wisconsin-Milwaukee.

Erin Taylor, a former PhD student in the O'Brien lab, rejoined us to participate in a career panel at the annual Biological Chemistry Department Retreat at WK Kellogg Biological Station. Erin is now an assistant professor at Carroll University in Wisconsin.

Welcome to Corri Hickson and Jake Firby! Corri, an incoming PIBS PhD student, will be doing a fall research rotation in the O'Brien lab. She completed her undergraduate studies in Chemistry at Amherst College. Jake, an incoming Biological Chemistry MS student, will be doing his thesis research in the O’Brien lab. He completed his undergraduate studies in Biochemistry and Biophysics at UM.

August 2025

Congratulations to Garret, Kellen, and Rachel for successfully completing their summer research with outstanding talks and posters! We wish them well in their upcoming terms.

June 2025

Three undergraduate students started summer research projects in the lab. Rachel Edwards joins us from North Carolina State University, Garret Eichlin joins us from Boston College, and Kellen Garris joins us from Amherst College.

May 2025

Members of the lab didn't have to travel far to attend the Midwest DNA Repair Symposium, which was held at the University of Michigan this year. Many thanks to Agnieszka Lukaszewicz and Mats Ljungman for organizing the conference.

April 2025

Senior graduate student David Beier presented his research to the department in the Graduate Student Research Seminar Series.

The research article "Molecular basis for RNA discrimination by human DNA ligase 1" is in press at Nucleic Acids Research and available online. The study shows how human LIG1 achieves high specificity for DNA by utilizing an aromatic RNA gate to discriminate against ribonucleotides throughout the ligase reaction cycle and is a collaboration between the O'Brien lab (former PhD student Tom Jurkiw, former undergraduate student Neha Bokil, Suzanne, Pat) and researchers from NIEHS (Percy Tumbale, Juno Krahn, Lars Pedersen, Jessica Williams, Tom Kunkel, Scott Williams).

January 2025

Pat O'Brien began a five-year term as an Associate Editor of Journal of Biological Chemistry on January 1.

November 2024

Jenna Veenstra's paper, "Rare Variants of DNA Ligase I Show Distinct Mechanisms of Deficiency," is in press at JBC and available online. Co-authors with Jenna and Pat are collaborator Charlotte Cunningham-Rundles and lab alumni Alexi Chabez (MS student), Terrance Haanen (rotation student), and Austin Keranen (summer undergraduate).

David Beier gave a research talk at the UM Genome Instability Meeting.

October 2024

Happy "UMich-iversary" to Michael Baldwin, who was honored with a Service Award for his 20 years of employment at Michigan Medicine. Michael joined the O'Brien lab as our lab manager shortly after Pat started in the department, so it is a milestone year for Pat too. 

Pat O'Brien and David Beier attended the 44th Midwest Enzyme Chemistry Conference at the University of Notre Dame.

September 2024

Jim Daley's design was chosen as the program cover for the annual Biological Chemistry Department Retreat at Maumee Bay Lodge & Conference Center in Ohio.

Jamie Cronk, an undergraduate student at UM, joined the O'Brien lab to work with Michael Baldwin.

Rosella Stowers, an incoming PIBS PhD student, did a fall research rotation in the O'Brien lab.

July 2024

Jenna Veenstra defended her doctoral dissertation "Mechanism of Human DNA Ligase I and Candidate LIG1 Syndrome Mutants." Jenna now has a teaching position at Dordt University in Sioux Center, IA.

June 2024

Pat O'Brien and collaborator Ariel Afek from the Weizmann Institute of Science traveled to Traverse City, MI, to give research talks at the D. Dan and Betty Kahn Scientific Symposium: Frontiers in Biomedical Research.

May 2024

McKenna Diermeier, an undergraduate student at Upper Iowa University in Fayette, joined the lab for the summer to work with Michael Baldwin.

David Beier received the Best Talk Award at the 2024 Midwest DNA Repair Symposium in Louisville, KY.  The title of his prizewinning presentation was "The Biochemical Impact of the LIG1 K845N Mutant on the Fidelity of DNA Ligation."

Aiden Jackson, an undergraduate student at UM, joined the O'Brien lab to work with David Beier.

April 2024

Maria Shamraj received her MS degree, after presenting her research at the annual MS Symposium and submitting her thesis: "Substrate Specificity of DNA Ligase I: Discrimination Against Ribonucleotide Substitutions in Okazaki Fragment Maturation."