In Science this week, researchers from Germany's Walter Schottky Institute show how discrete three-dimensional DNA components can self-assemble in solution on the basis of shape complementarity and without base pairing. Using this principle, they created a series of homo- and heteromultimeric objects including an actuator and a switchable gear. They also demonstrate that the balance between attractive and repulsive interactions — and thus the design of the assemblies — may be finely controlled by global parameters such as cation concentration or temperature and by an allosteric mechanism based on strand-displacement reactions. The discovery could help in the creation of dynamic macromolecular devices and assemblies as scaffolds for various purposes including advanced therapeutics.
Also in Science, Rockefeller University researchers report the results of a whole-exome sequencing study of a young child believed to have rare genetic mutations that make her and her parents especially susceptible to influenza virus infection. They found that both parents harbored a mutation in alleles affecting the IRF7 gene, which encodes a transcription factor that stimulates interferon production in response to viruses. They also discovered that many of the child's skin and immune cells did not produce type I and III interferons in response to influenza infection, allowing the virus to replicate virtually unchecked. The findings point to IRF7 as a key factor against flu infection and suggest that single-gene inborn errors may be responsible for the most severe cases of the disease.