University of MichiganGene expression is known to be the process at the core of a biological function that appears to instruct a cell what to do. A new Michigan University research sheds light on how mechanical forces could have an affect on this gene expression. The researchers seem to have observed that tension on DNA molecules could influence the expression of genes.

While the chemistry involved in gene expression is believed to have been comprehended by scientists very little is known about the physics. Claimed to be the premier team to actually exhibit a mechanical effect that could be at play in this process, these findings could hold new meaning to understanding gene regulation. Improved understanding of how cells may regulate themselves could offer novel insights into how the process could fail and result in a disease.

“We have shown that small forces can control the machinery that turns genes on and off. There’s more to gene regulation than biochemistry. We have to look at mechanics too,” remarked Jens-Christian Meiners, associate professor in the Department of Physics and director of the biophysics program.

“When cells start to misinterpret regulatory signals, cardiac disease, birth defects, and cancer can result. In fact, mechanical signals have been implicated as a culprit in a variety of pathologies,” added Joshua Milstein, a research fellow in the Department of Physics.

The scientists employed custom ‘optical tweezers’ or lasers to conduct their experiment. This enabled them to pull on the ends of bacterial DNA strands with 200 femtonewtons of force, mentioned Yih-Fan Chen, a doctoral student in the Department of Biomedical Engineering. The tweezers were fabricated and built by Chen. The force used by them apparently corresponded roughly to the weight of one-billionth of a grain of rice. The investigators noticed a 10-fold decrease in the rate at which the strands looped in on themselves in DNA segments that were seemingly tethered to a microscope slide.

Genes from within the loops are reportedly prevented from being expressed due to DNA looping. Seen as a common mechanism for gene regulation, it may also occur in complex organisms including humans. With specialized proteins acting as buckles to connect distant points on the DNA to form the loops, experts claim it to be the chemistry part. However understanding how the DNA bends allowing those distant points to come together seems to be the challenge for physics.

This experiment was conducted on free DNA. According to the scientists, forces as much as 100 times stronger in the meantime are regularly created inside cells as contents shift and buffet each other.

“If we can basically shut this process down with the tiniest force, how could all these larger forces not have an impact on gene expression?” Milstein revealed. “We can tell you how long you’ll have to wait for a DNA loop to form based on how much force you apply to the DNA. We’re one step closer to understanding cells quantitatively.”

Hoping to acquire a quantitative understanding of this biological process Meiners and his team liken the current state of our understanding of gene expression to a diagram. In search for equations, experts claim these results to start providing that.

The paper called ‘Femtonewton Entropic Forces Can Control the Formation of Protein-Mediated DNA Loops’ is published in the current edition of Physical Review Letters.