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 ?
The abundance of a sequence in protected nucleosomes was determined by real-time quantitative polymerase chain reactions (qPCRs) performed in triplicate.
Z-containing nucleosomes mediate the thermosensory response in arabidopsis.
Decondensation of mouse sperm chromatin and reassembly into nucleosomes mediated by polyglutamic acid in vitro.
The binding of lupus-derived autoantibodies to the C-terminal peptide (83-119) of the major SmD1 autoantigen can be mediated by double-stranded DNA and nucleosomes.
The spacing between nucleosomes is broader, they found, when the nucleosomes are in DNase I hypersensitivity sites, presumably because of chromatin remodeling due to transcription factor binding.
Lupus Erythematosus (LE) is the root designation for a diverse array of illnesses that are linked together by the development of autoimmunity directed predominantly at the molecular constituents of nucleosomes and ribonucleoproteins.
These clusters of folded DNA on a reel are called nucleosomes.
The nucleosomes are then further packed, making up the chromatin, which in human cells is distributed into 46 structures, chromosomes.
The NuQ tests are based on the science of Nucleosomics which is the practice of identifying and measuring nucleosomes in the bloodstream an indication that cancer is present.
Transcriptionally active genes are generally characterized by nonmethylated CpG dinucleotides in promoter regions, and nucleosomes arranged in a more disperse manner that favors access to transcription factors and other regulatory proteins.
The complete profile includes antibodies for: U1-nRNP, SS-A, Ro-52, SS-B, Scl-70, Pm-Scl, Jo-1, Centromere B, PCNA, anti-dsDNA, nucleosomes, histones, ribosomal P Protein, AMA M2).