Life's not quite as organised as previously thought..

Scientists at The Salk Institute and UCSD have used BioStatus's premier DNA dye - DRAQ5™ - to demonstrate that contrary to current thinking, chromatin is actually much less structured than previously thought.  

This far-reaching breakthrough research by Ou et al. published in Science magazine relies upon DRAQ5 which, uniquely, on excitation catalyses polymerisation of DAB to chromatin.  This then permits labeling of chromatin with the standard electron microscopy contrast agent osmium tetroxide to accumulate on this DAB-labeled chromatin. This process is efficient yet exposes the cells and their contents to the least possible perturbation. The sample is then ready for 3D imaging by electron microscope tomography which the authors have called ChromEMT.

Advanced statistical analysis of the 3D images of nuclei within both interphase and mitotic cells showed significant differences from each other but perhaps most strikingly they showed that existing models for chromatin ultrastructure, based on more aggressive sample preparation approaches, apparently over-estimate the higher order structures and did not indicate the range of structures this new work has uncovered.

Exciting possibilities for this technology might include the differences between healthy and diseased cell phenotypes amongst many other fundamental questions.

As longer wavelength excitation was a requirement the authors screened available far-red DNA dyes and amongst these only DRAQ5 engendered the DAB labeling of chromatin that was essential to achieve their technical goal.

WHERE TO BUY

Read a quick overview at Genomeweb: https://www.genomeweb.com/genetic-research/chromatin-structure-less-organized-textbooks-say-according-new-study 

If you have more time, read the original article: http://science.sciencemag.org/content/357/6349/eaag0025

Read more articles on DRAQ5™ in exciting new EM techniques: 
Simplified CLEM - from in vivo imaging to FIB/SEM
CryoChem for CLEM - preservation of high definition in fluorescence & EM dimensions