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.
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