Volume 7 Issue 8, August 2010

Linked fluorescent proteins are used to visualize voltage in living mouse brains.

A panel of advanced methods reveals that retrotransposable elements are more prevalent than suspected in human genomes.

Visualization of newly synthesized proteomes using conventional fluorescence microscopy reveals the local nature of protein translation.

Researchers solve a high-resolution structure of a seven-helix transmembrane protein using nuclear magnetic resonance (NMR) spectroscopy.

Analysis of RNA sequencing data points to fewer intergenic transcripts than assumed. Isolating them via chromatin association may enrich for functional noncoding transcripts.

To site-specifically label proteins in living cells, researchers mutate an enzyme to recognize a small fluorophore and catalyze its attachment to a small peptide tag.

Nanotube arrays, imprinted with proteins, can be used as biosensors.

Overall safety is increasing, but new safety hazards, such as repetitive stress injuries and potential toxicities from nanoparticles, are coming under closer scrutiny.

Mutations that increase the dynamic range of a photoswitchable protein may be used to improve other such photoswitches and increase their potential for allosteric control of protein activity in live cells.

Two methods describing gene expression and chromatin profiling of small cell numbers make progress toward achieving comprehensive integrated molecular views of defined cell populations.

A platform for automated screening of zebrafish larvae in high throughput should allow detection of phenotypic changes in single cells.

Improving the protocols for chromatin immunoprecipitation and library construction for the Illumina Genome Analyzer allows for chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-seq) experiments on input samples as small as 10,000 cells and yields information on bivalent chromatin domains in hematopoietic progenitor cells.

On-flowcell capture and reverse transcription followed by single-molecule cDNA sequencing provides reproducible digital gene expression results from as few as 1,000 cells.

Light-sensitive LOV domains show much promise for engineering proteins with photoswitchable activity. The dynamic range of a LOV domain is now substantially improved by the introduction of beneficial mutations predicted by an analytical model of photoswitching. The approach should prove useful to improve the function of multiple LOV-based switches.

A monomeric fluorescent protein that can be irreversibly photoswitched from green to red form, both of which can be reversibly photoactivated, is reported. It is applied to pulse-chase experiments in which dynamic structures in live cells are imaged with superresolution using photoactivation localization microscopy (PALM).

Single integration of a target gene expressing MS2-binding stem loops allows the real time quantification of transcriptional bursts, promoter firings and cell cycle–dependent transcription rates.

A platform for rapid and automated imaging and laser manipulation of zebrafish larvae is presented. It should permit large-scale chemical and genetic screens in this vertebrate organism.

The combination of digital scanned laser light sheet microscopy and incoherent structured illumination allows intrinsic removal of scattered background fluorescence from the desired fluorescent signal. This provides substantial advantages for imaging nontransparent organisms and allowed reconstruction of a fly digital embryo from a developing Drosophila embryo.

Genetically encoded voltage-sensitive fluorescent proteins can be used to measure electrical activity from selected populations of neurons. This study demonstrates that these probes, when expressed in pyramidal cells of mouse somatosensory cortex, can report electrical responses in vivo. These proteins are a complementary tool to calcium imaging techniques for optical functional brain imaging.

Noncontact, frequency-modulation atomic force microscopy (FM-AFM) can be used to measure the microrheological properties of soft samples at acoustic frequencies. The method will be useful for characterizing the elasticity and viscosity of tissues that detect or produce sound.

Multiphoton laser-scanning microscopy paired either with stationary line scans across a vessel or moving line scans across a network of vessels allows the profiling of key parameters that describe red blood cells.