Synchronized cameras catch messenger RNA on the run

Messenger RNA (mRNA) is the shuttle that carries genetic information across a cell’s nuclear membrane and into the cytoplasm, where the information is translated into a protein sequence. However, the movement of mRNA, which is about 25 nm in diameter, through the nuclear pore complex, roughly 120 nm in diameter, has been difficult to resolve visually since both mRNA and the NPC are well below the 200-nm diffraction limit for optical microscopes. Now, Robert Singer at Yeshiva University’s Albert Einstein College of Medicine in New York and David Grünwald at the Delft University of Technology in the Netherlands have developed a new nanometer-resolution imaging technique that they used to track mRNA’s passage. Emission signals from mRNA and the NPC—labeled with spectrally different fluorescent probes and shown in the image as green and red, respectively—were chromatically separated and tracked by two synchronized high-speed CCD cameras. The researchers achieved 26-nm spatial resolution...