nucleosome


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Nucleosome

The fundamental histone-containing structural subunit of eukaryotic chromosomes. In most eukaryotic organisms, nuclear deoxyribonucleic acid (DNA) is complexed with an approximately equal mass of histone protein. The nucleosome is organized so that the DNA is exterior and the histones interior. The DNA makes two turns around a core of eight histone molecules, thus forming a squat cylinder 11 nanometers in diameter and 5.5 nm in height. A short length of linker or spacer DNA connects one nucleosome to the next, forming a nucleosomal chain that has been likened to a beaded string. This basic structure is found in all forms of chromatin. Nucleosomes have been found in all eukaryotic organisms examined, the only exceptions being some sperm nuclei and the dinoflagellate algae.

A chain of adjacent nucleosomes is approximately sixfold shorter than the DNA it contains. Moreover, chains of nucleosomes have the property of self-assembling into thicker fibers in which the DNA packing ratio approaches 35:1. These observations, and the lack of any obvious catalytic activity, have led to the assumption that the primary function of the nucleosome consists of organizing and packing DNA. See Chromosome, Deoxyribonucleic acid (DNA), Gene

nucleosome

[′nü·klē·ə‚sōm]
(cell and molecular biology)
A morphologically repeating unit of deoxyribonucleic acid (DNA) containing 190 base pairs of DNA folded together with eight histone molecules. Also known as v-body.
References in periodicals archive ?
First, the SCQCMs based on M-cfDNA have biological properties similar to those of plasma cfDNA species, such as fragments associated with nucleosome core particles and trimmed nucleosomes (18, 25).
NK cells were shown to be the predominant cell-expressing gzms, and deficiency of gzmA and gzmB was associated with increased bacterial loads accompanied by augmented nucleosome release at the primary site of infection (suggestive of local cell death), earlier signs of liver necrosis, and more renal dysfunction.
According to the company, the patent relates to its Nucleosomics platform for the detection of changes in fragments of chromosomes, called nucleosomes.
DNA-dependent phosphorylation of histone H2A.X during nucleosome assembly in Xenopus laevis oocytes: involvement of protein phosphorylation in nucleosome spacing.
Poirier, "Post-translational modifications of histones that influence nucleosome dynamics," Chemical Reviews, vol.
But what about DNA guarded by a nucleosome? Could we expect a predominance of intact DNA sequences from nucleosome-bound DNA?
The smallest unit of chromatin is the nucleosome acetylases switch genes on by freeing DNA from tightly packed chromatin.
There are many interesting questions about the origin and nature of circulating cell-free DNA; many have noted that the fragment size is roughly that of what can be wrapped around a nucleosome. The sequencing of cell-free DNA and mapping it back to the chromosome of origin have revealed a significant periodic enhancement near transcription start sites (6).
He was a postdoctoral fellow and member of the scientific staff at the Laboratory of Molecular Biology in Cambridge, England, where he discovered the nucleosome, the basic unit of DNA coiling in chromosomes.
In total, 92.3% of the patients were ANA positive, and the most common autoantibodies were dsDNA (44.4%), RNP/Sm (20.8%), nucleosome (20.8%), SS-A (18.1%), and Ro-52 (16.7%).
Histones are highly evolutionary conserved proteins, which are essential in the composition of the nucleosome of eukaryotic chromatin.