Definitions for nucleosome
ˈnu kli əˌsoʊm, ˈnyu-nu·cle·o·some

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1. nucleosomenoun

   Any of the subunits that repeat in chromatin; a coil of DNA surrounding a histone core

WikipediaRate this definition:0.0 / 0 votes

1. Nucleosome

   A nucleosome is the basic structural unit of DNA packaging in eukaryotes. The structure of a nucleosome consists of a segment of DNA wound around eight histone proteins and resembles thread wrapped around a spool. The nucleosome is the fundamental subunit of chromatin. Each nucleosome is composed of a little less than two turns of DNA wrapped around a set of eight proteins called histones, which are known as a histone octamer. Each histone octamer is composed of two copies each of the histone proteins H2A, H2B, H3, and H4. DNA must be compacted into nucleosomes to fit within the cell nucleus. In addition to nucleosome wrapping, eukaryotic chromatin is further compacted by being folded into a series of more complex structures, eventually forming a chromosome. Each human cell contains about 30 million nucleosomes.Nucleosomes are thought to carry epigenetically inherited information in the form of covalent modifications of their core histones. Nucleosome positions in the genome are not random, and it is important to know where each nucleosome is located because this determines the accessibility of the DNA to regulatory proteins.Nucleosomes were first observed as particles in the electron microscope by Don and Ada Olins in 1974, and their existence and structure (as histone octamers surrounded by approximately 200 base pairs of DNA) were proposed by Roger Kornberg. The role of the nucleosome as a regulator of transcription was demonstrated by Lorch et al. in vitro in 1987 and by Han and Grunstein and Clark-Adams et al. in vivo in 1988. The nucleosome core particle consists of approximately 146 base pairs (bp) of DNA wrapped in 1.67 left-handed superhelical turns around a histone octamer, consisting of 2 copies each of the core histones H2A, H2B, H3, and H4. Core particles are connected by stretches of linker DNA, which can be up to about 80 bp long. Technically, a nucleosome is defined as the core particle plus one of these linker regions; however the word is often synonymous with the core particle. Genome-wide nucleosome positioning maps are now available for many model organisms including mouse liver and brain.Linker histones such as H1 and its isoforms are involved in chromatin compaction and sit at the base of the nucleosome near the DNA entry and exit binding to the linker region of the DNA. Non-condensed nucleosomes without the linker histone resemble "beads on a string of DNA" under an electron microscope.In contrast to most eukaryotic cells, mature sperm cells largely use protamines to package their genomic DNA, most likely to achieve an even higher packaging ratio. Histone equivalents and a simplified chromatin structure have also been found in Archaea, suggesting that eukaryotes are not the only organisms that use nucleosomes.

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1. nucleosome

   A nucleosome is a structural unit of chromatin, consisting of a segment of DNA wrapped around eight histone proteins. Nucleosomes help organize and compact the DNA in the cell nucleus, regulating access to genes and playing a role in gene expression.

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1. Nucleosome

   A nucleosome is the basic unit of DNA packaging in eukaryotes, consisting of a segment of DNA wound in sequence around eight histone protein cores. This structure is often compared to thread wrapped around a spool. Nucleosomes form the fundamental repeating units of eukaryotic chromatin, which is used to pack the large eukaryotic genomes into the nucleus while still ensuring appropriate access to it. Nucleosomes are folded through a series of successively higher order structures to eventually form a chromosome; this both compacts DNA and creates an added layer of regulatory control, which ensures correct gene expression. Nucleosomes are thought to carry epigenetically inherited information in the form of covalent modifications of their core histones. Nucleosomes were observed as particles in the electron microscope by Don and Ada Olins and their existence and structure were proposed by Roger Kornberg. The role of the nucleosome as a general gene repressor was demonstrated by Lorch et al. in vitro and by Han and Grunstein in vivo.

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Numerology

1. Chaldean Numerology

   The numerical value of nucleosome in Chaldean Numerology is: 3

2. Pythagorean Numerology

   The numerical value of nucleosome in Pythagorean Numerology is: 5

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References

1. ^ Wiktionary
   https://en.wiktionary.org/wiki/Nucleosome
2. ^ Wikipedia
   https://en.wikipedia.org/wiki/Nucleosome
3. ^ ChatGPT
   https://chat.openai.com
4. ^ Wikidata
   https://www.wikidata.org/w/index.php?search=nucleosome