Telomere Researcher Ci Ji Lim Named Pew Biomedical Scholar

Ci Ji Lim, a University of Wisconsin–Madison biochemistry professor, has been named a 2024 Pew Biomedical Scholar by the Pew Charitable Trusts. He is one of 22 of the latest early-career scientists to receive the honor, joining the ranks of more than 1,000 Pew Scholars recognized since 1985 for their outstanding promise in science relevant to human health and with particularly creative and innovative approaches to their work.

Lim’s research focuses on telomeres, the protective caps made of repetitive DNA sequences and proteins found at the ends of human chromosomes. Telomeres guard the ends of chromosome from being erroneously identified as broken DNA ends, which could lead to modifications that impair the DNA’s stability. Telomere length decreases as we age, and dysfunction in telomere formation and maintenance is associated with cancer and premature aging diseases.

Scientists today liken telomeres to a cell phone’s rechargeable battery, which holds less and less charge over time. A phone’s battery life also depends on factors other than its age, such as how many apps are open and how the phone is used. Similarly, Lim believes that the length and function of telomeres are contingent on factors besides cellular age. Among these factors are the abundance and locations of proteins that bind along the telomeric DNA.

Existing tools to study protein-DNA interactions rely on unique DNA sequences, making it difficult to investigate similar interactions in a telomere. As a Pew Biomedical Scholar, Lim will develop innovative methodologies to study the profile of protein distributions at telomeres.

“A lot of times, we biochemists strategically minimize the complexity of the systems we are studying to aid experimental interpretation. But then we also want to think about how our biochemical findings translate into what’s happening in the cell,” says Lim. “In the case of telomeres, understanding protein-DNA interactions in short, isolated pieces of telomeric DNA does not necessarily capture what would happen when the same sequence is repeated thousands of times, as it is at the end of each of our chromosomes,” explains Lim. “A missing piece in our understanding of telomere biology is how proteins are arranged along the repetitive telomeric DNA.”

Pew scholars are chosen by an advisory committee of notable scientists and are invited to an annual meeting of their peers to discuss their research. They also receive $300,000 in research support over four years.

Lim received his Ph.D. in integrative sciences and engineering from the National University of Singapore in 2014, under the mentorship of Professor Jie Yan, an expert in single-molecule biophysics and theoretical modeling. In 2020, he completed his postdoctoral training in biochemistry and structural biology with Professor Tom Cech at the University of Colorado Boulder and subsequently joined UW–Madison as an assistant professor of biochemistry. In 2022, Lim received a High Risk, High Reward New Innovator Award from the National Institutes of Health to study the human telomere chromatin landscape.

Written by Renata Solan.