Nucleosomes

Part of speech: noun

Definitions

1. A complex of DNA and histone proteins that forms the fundamental unit of chromatin in eukaryotic cells; serving as a scaffold for DNA packaging and regulation of gene expression; facilitating the compaction of genetic material into a condensed structure within the nucleus of a cell
2. Structures composed of DNA wrapped around histone proteins, essential for the organization of genetic material; they play a critical role in regulating access to DNA for transcription and replication; helping to ensure proper chromatin formation and function
3. Discrete units of DNA and histones that create a repeating structural motif in chromatin, crucial for the storage and regulation of genetic information; they assist in controlling gene activity and maintaining DNA integrity during cell division

Etymology: "Nucleosomes" is the plural of "nucleosome", the name for the basic repeating unit of chromatin, the DNA-and-protein material that packs the genome inside a cell's nucleus. Each nucleosome is a short length of DNA wound around a core of histone proteins, and a cell's genome is strung along these beads like thread on a necklace. The word was coined in 1975 by P. Oudet and colleagues, who needed a name for a structure that earlier researchers had described under the older label "nu body." The new term combines "nucleo-", from the Greek-derived "nucleus," meaning the cell's central compartment, with "-some," a suffix from the Greek "soma," meaning body. The name thus keeps the older "nu body" idea while expressing it in a more systematic form built from classical roots.