Author Sahand Hormoz describes the work represented on the latest cover of the Biophysical Journal, based on her recent paper, "Cross-talk and interference enhance information capacity of a signaling pathway."

This image is a visual representation of a new perspective on gene regulation: gene regulation as a communication channel. Communication channels commonly refer to exchange of binary bits, 0s and 1s. This digital information transmission permeates our daily lives in the form of cells phones, internet, etc. Living organisms, cells in particular, can also be thought of as information processing agents. DNA, for instance, is almost a direct analogue of a computer's hard drive, where the binary bits of information are replaced by the four types of nucleotides. More abstractly, the signaling molecules that regulate various cellular functions can also be regarded as carriers of information about the cell's environment. This information is very noisy since the signaling molecules are subject to thermal fluctuations. The cell then needs to develop ways to reliably extract information from these noisy signaling molecules to learn about its environment. Biological mechanisms for dealing with noisy sources of information is the essence of the work discussed in the paper. In this image, we see two types of transcription factors (shaded yellow and purple) in various stages of binding to a DNA strand (shaded silver). These transcription factors are the input signaling molecules. We see a schematic representation of the transcriptions factors in their molecular form and also as abstract bits of information 0s and 1s. There are two streams of information into the transcriptional machinery that in turn outputs another stream of bits (shaded green) corresponding to the product of the target gene. The output molecules can themselves be inputs regulating other genes or signaling other cells. In the image, we try to juxtapose the abstract information content of the transcription factors with their physical molecular form.

I am delighted to see this image featured on the cover of the Biophysical Journal. As a theoretical physicist, I rarely get a chance to "see" any of the systems that I work on. However, for any problem, I start by constructing a conceptual picture piece by piece, which hopefully eventually reveals some new insight. Thinking in terms of pictures is very familiar; transferring a picture from the imagination to the computer screen, however, was challenging. My goal was to communicate a complex idea in the form of a simple conceptual picture that was also visually appealing. If this image inspires a broader audience and generates excitement about this work, the effort was certainly worthwhile.

- Sahand Hormoz