In Science, a team from California reports on a class of genetic control systems called molecular network diverters that interface with a native signaling pathway to "route cells to divergent fates in response to environmental signals without modification of native genetic material." They also describe a method for identifying control points within natural networks that enables the construction of synthetic control systems for activating or attenuating native pathways to direct cell fate. "Our ability to construct synthetic circuits that interface with native pathways, like molecular network diverters, will continue to expand as more pathway-responsive genetic elements and regulatory RNAs are identified," they add. "Advances in our capabilities to extract information from and direct responses in native pathways will facilitate the translation of synthetic biology tools to applications in medicine and biotechnology."
Also in this week's Science, researchers from Columbia University, the Massachusetts Institute of Technology, and New York University call for a simple and universal classification system for neurons, noting that the "anatomical, electrophysiological, and biochemical diversity of nerve cells" has made it impossible to determine how many types of nerve cells exist in the mammalian nervous system. To create such a system, they suggest that future studies focus on single-cell RNA sequencing, which allows for fingerprinting of specific cellular states and can reveal the structure and behavior of individual neurons, as well as their genetic influences. "A universally applicable classification system should be based on traits that are objectively quantifiable, sufficiently diverse, and reproducible in independent laboratories," the researchers argue. "Such a classification method would provide new insights into CNS organization, development, and function, and might reveal unexpected relationships between neuronal subtypes."