UB Study Visually Depicts Anti-Cancer DNA Repair Process

Bianco’s project seeks to understand how enzyme-related processes contribute to the regression and subsequent restoration of stalled DNA replication forks.

His four-year grant is from the National Institute of General Medical Sciences.

Bianco’s research will illuminate cellular repair-and-restart processes that occur as cells copy, or replicate, their DNA.

During this process, the cellular machinery derails when it encounters DNA damage or other types of blockages, Bianco explains.

“Repair enzymes must then fix the roadblock and get DNA replication going again,” he says. “If this fails, the cell dies or turns into a cancerous cell.”

Therefore, “understanding how stalled DNA replication forks are rescued is important, as defects in these repair mechanisms in higher organisms lead to the accumulation of mutations that, in turn, lead to cancer,” Bianco explains.

“Our contribution is significant because it will allow, for the first time, a clear understanding into the range of events that transpire to reactivate a stalled DNA replication fork in vivo,” he says.

Bianco will use innovative techniques to visually depict how stalled DNA replication forks regress and are subsequently restored.

Using bulk-phase biochemistry, atomic force microscopy and a novel fluorescence-based single molecule technique he developed, Bianco aims to determine the mechanism of key recombination helicases—enzymes that separate DNA helix strands—in fork reactivation.

This will clarify how these enzymes bind to and process fork substrates that mimic both stalled and regressed forks.

Critical to the success of the project is the use of two novel, single DNA molecule approaches to produce high-resolution, “real-time movies” of the molecular events occurring at stalled DNA replication forks, Bianco says.

Bianco is collaborating with Yuri Lyubchenko, PhD, professor of pharmaceutical sciences at the University of Nebraska Medical Center.