Dr. Gürol Süel, assistant professor of pharmacology, said his research and that of his colleagues published today in the journal Science represents "a new paradigm," suggesting that rather than being bad for biology, cellular noise might have an important function, such as prompting stem cells to transform into a specific tissue type.
Electronic noise is an unwanted signal characteristic of all electrical circuits, typically caused by random fluctuations in the electric current passing through the components of a circuit. Similarly, within each living cell there are myriad "genetic circuits," each composed of a distinct set of biochemical reactions that contribute to some biological process. Randomness in those reactions contributes to biological noise, technically referred to as stochastic fluctuations.
"Noise in biological systems is a fact of life," said Dr. Süel, a member of the systems biology division of the Cecil H. and Ida Green Comprehensive Center for Molecular, Computational and Systems Biology at UT Southwestern. "Even though each cell may have the same set of genes turned on – the same hard-wired genetic circuit – there will still be slight variations in the amount of the various proteins those genes produce, some fluctuation in the amount of each circuit component. No two cells are alike in terms of their chemical composition."
Conventional scientific thinking has been that the random nature of such fluctuations within cells interferes with the reliable operation of biological systems. However, Dr. Süel's research team hypothesized that noise in one particular genetic circuit might be beneficial, linked to a process that controls cell fate.
To determine the biological role for noise, the researchers analyzed a genetic circuit that controls the transformation of bacteria cells from one state to another. This process, called differentiation, is akin to that used by human stem cells to change into a specific tissue type.
In a series of theoretical calculations and actual experiments, the researchers found that the particular circuit they investigated appears to have evolved in this bacterium to amplify cellular noise. Dr. Süel and his colleagues determined that by dampening the noise level within the bacterial cells, they could prevent the cells' transformation between states, essentially "tuning" cellular behavior.
"The amplitude of cellular noise correlates with the probability of triggering differentiation," Dr. Süel said. "This is experimental evidence that a genetic circuit utilizes noise to drive a biological process."
Typically, scientists examine genes and proteins individually to try to determine their functions within a cell. However, Dr. Süel said that's like examining each capacitor or switch in an electrical circuit in an attempt to understand the function of the electrical device in which the circuit is housed.
"Our research provides a systems-level view of how gene circuits work as a whole," he said.
Dr. Süel said the next step in his research would be to uncover the theoretical design principles of genetic circuits and what role interactions between distinct circuits play in regulating complex biological processes, such the differentiation of multipotent stem cells.
Dr. Süel, who earned his doctorate in molecular biophysics from UT Southwestern, carried out much of the work for the Science paper while a postdoctoral research fellow at the California Institute of Technology. He joined the UT Southwestern faculty in November and is an Endowed Scholar in Biomedical Research.
Other co-authors on the Science paper are Rajan Kulkarni and senior author Michael Elowitz, both of Caltech; Jonathan Dworkin of Columbia University; and Jordi Garcia-Ojalvo of the Universitat Politecnica de Catalunya in Spain.
The work was funded in part by the National Institutes of Health, the Searle Scholars Program and the Human Frontier Science Program.
Amanda Siegfried | EurekAlert!
How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH
A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
23.06.2017 | Physics and Astronomy
23.06.2017 | Physics and Astronomy
23.06.2017 | Information Technology