In Science this week, researchers from the Université de Montréal report on their study of the role of the Hedgehog pathway in the function of the blood-brain barrier. They found that astrocytes secrete Sonic hedgehog and that the endothelial cells of the blood-brain barrier express Hedgehog receptors. "Using pharmacological inhibition and genetic inactivation of the Hh signaling pathway in ECs, we also demonstrated a critical role of the Hh pathway in promoting the immune quiescence of BBB ECs by decreasing the expression of pro-inflammatory mediators and the adhesion and migration of leukocytes, in vivo and in vitro," the authors write.
Jay Keasling and his colleagues have an article in this week's Science in which they discuss their way of developing an RNA-regulated device to control gene expression. "We formulated a design-driven approach that used mechanistic modeling and kinetic RNA folding simulations to engineer RNA-regulated genetic devices that control gene expression," the authors write. The devices were then constructed and tested in E. coli. "Our work establishes a foundation for developing computer-aided design platforms to engineer complex RNA-based control systems that can process cellular information and program the expression of very large numbers of genes, enabling both increased understanding of fundamental biological processes and applications to meet demands for new therapies, renewable fuels, and chemicals," Keasling and his colleagues say.
The University of California, Berkeley's Carlos Bustamante and colleagues report on the ribosome's function in protein folding. Using optical tweezers, the researchers were able to study how a stalled, ribosome-bound nascent T4 lysozyme. "Our findings may represent a paradigm for how the ribosome can, in principle, affect nascent-chain folding," the researchers write.
Researchers led by Jonathan Weissman report in an online, advance article of Science that they used ribosome profiling to monitor meiosis in yeast. From this, they found that "genome coding has a complexity not captured by existing annotations. Ribosome profiling also captured a layer of regulation that is invisible to mRNA measurements, revealing extensive and dynamic translational regulation of canonical ORFs." In addition, the researchers say that "this study also gives a holistic view of the metabolic and cellular reorganization seen through the yeast meiotic program, extending beyond a traditional chromosome-centric picture."