In this week's Nature, researchers from the University of California, San Diego, describe the use of protease competition to engineer rapid and tunable genetic circuits across multiple spatial and temporal scales. They characterized coupling delay times that are more than an order of magnitude faster than standard transcription factor-based coupling methods and demonstrated tunability through manipulation of the linker between the protein and its degradation tag. This mechanism serves as a platform to couple genetic clocks at the intracellular and colony level, and then synchronizes the multi-colony dynamics to reduce variability in both clocks. This coupled-clock network can be used to encode independent environmental inputs into a single time series output, thus enabling frequency multiplexing in a genetic circuit context.
Also in Nature, a team from Peking University describes the development of a CRIRPR lentiviral library in human cells as well as a method of gene identification based on functional screening and high-throughput sequencing analysis. Using knockout library screens, the researchers were able to uncover what host genes were essential for the intoxication of cells by anthrax and diphtheria toxins. Expanding the application of this genetic screening approach is expected to facilitate the rapid identification of genes important for bacterial toxicity, and will also enable the discovery of genes that participate in other biological processes, the researchers say.