Related Experiment Video
Updated: Aug 1, 2026

Visualization of DNA Compaction in Cyanobacteria by High-voltage Cryo-electron Tomography
Published on: July 17, 2018
DNA compaction during intense transcription measured by electron microscope tomography
Abstract:
Thick sections (0.5-1.0 micron) containing pilocarpine-hyperstimulated Balbiani ring (BR) genes of Chironomus tentans salivary glands were reconstructed by electron microscope tomography (EMT). Six transcription loops were analyzed at low resolution permitting a measurement of transcription unit length in situ. Comparison of the average transcription unit length with the BR gene coding region DNA length yields an estimate of the DNA compaction ratio in situ. The estimated DNA compaction ratio (approximately 3-fold) is consistent with a significant degree of nucleosome unfolding in the hyperstimulated BR genes.
Related Concept Videos
Genomic DNA in Eukaryotes
DNA Packaging
The Nucleosome
DNA is wound twice around a protein complex called histone core, that consist of 8 histone proteins. This complex...
Chromatin Packaging
The chromatin
In combination with specialized DNA binding protein called Histones, the DNA double helix forms a compact DNA: protein complex called chromatin. The chromatin itself is further compacted into higher-order structures.
The Nucleosome
In a chromosome, DNA is wound twice around a protein complex called a histone octamer core, which consists of 8 histone proteins. This...
Chromatin Packaging

