University of Michigan Biophysics researchers have shown that slight forces on DNA molecules could play a role in gene expression---the process at the heart of biological function that tells a cell what to do.

Using custom “optical tweezers,” or lasers, the scientists tugged on the ends of E. coli DNA strands with 200-femtonewton forces approximating the weight of one-billionth of a grain of rice, said Yih-Fan Chen, a doctoral student in the Department of Biomedical Engineering. Chen designed and built the tweezers.

In the captive DNA threads, the scientists observed a 10-fold decrease in the rate at which the strands looped in on themselves.

DNA looping prevents genes within the loops from being expressed. A common mechanism for gene regulation, it also occurs in complex organisms including humans. Specialized proteins act as buckles to connect points on the DNA to form the loops.

The paper is called “Femtonewton Entropic Forces Can Control the Formation of Protein-Mediated DNA Loops.” and has been highlighted in the American Physical Society Physical Review Letters and on the main Physics site for APS.

Dr. Meiners recently spoke with UPI about this exciting development.

This research is funded by the National Institutes of Health and the National Science Foundation.

For more information: Jens-Christian Meiners