Reviews & Analysis

The tight interaction between the small molecule biotin and the tetrameric protein streptavidin is widely exploited for many different applications in protein science. In this issue, researchers present the design of a monovalent streptavidin tetramer with a single biotin binding site and demonstrate its enhanced properties over wild-type streptavidin for use in cell-surface protein labeling.

A new approach to generating large quantities of myeloid progenitor cells ex vivo will facilitate detailed studies of normal white blood cell differentiation and of abnormalities leading to blood disorders such as leukemia.

A recently developed multigene viral expression system is put to work to generate mice carrying a single T-cell receptor (TCR) specificity. Complementing the transgenic-mice technique, this method offers new practical options to researchers studying T-cell development.

A simple 'smart-pooling' screening strategy for large-scale systems biology experiments promises to provide considerable improvement in experimental efficiency, while simultaneously allowing improved accuracy and coverage.

Intracellular protein-protein interactions form the basis of most biological processes. Structural aspects of these reactions can now be analyzed in living prokaryotic cells and in atomic detail by nuclear magnetic resonance spectroscopy.

Understanding of the sequelae of cerebral microvascular injury has been hampered by a lack of animal models to enable precise localization of injury. In this issue, Nishimura et al. describe a stroke model that couples two-photon laser-scanning mapping of the cerebral cortex with femtosecond laser technology to produce three distinct microvascular injuries characterized by hemorrhage, vessel leakage or vessel occlusion.

The short nature of microRNAs (miRNAs) has presented unique obstacles to experimental biologists. Two research papers in this issue of Nature Methods describe solutions to some of these problems and provide high-resolution data on the expression patterns of these tiny regulatory RNAs.

A new carefully optimized and characterized genetically encoded fluorescent sensor for cyclic GMP (cGMP) has fast kinetics and properties that should make it an excellent compromise between sensitivity and specificity when compared to existing sensors.

A new caging group based on the nitrodibenzofuran chromophore has been developed with improved photochemical properties for both ultraviolet and two-photon photolysis applications, providing a new tool for the rapid and efficient release of calcium ions for biological studies.

A Xenopus embryo coinjected with a plasmid encoding a transgene and the φC31 integrase mRNA readily facilitates genomic integration resulting in healthy transgenic embryos.

The pathogenic arsenal of many bacteria includes an apparatus that mediates the injection of a cocktail of virulence proteins directly into host cells. Spatiotemporal aspects of this process can now be analyzed in living cells.