Search results
Results from the WOW.Com Content Network
Nucleosome core particles are observed when chromatin in interphase is treated to cause the chromatin to unfold partially. The resulting image, via an electron microscope, is "beads on a string". The string is the DNA, while each bead in the nucleosome is a core particle.
The arrangement of chromatin within the nucleus may also play a role in nuclear stress and restoring nuclear membrane deformation by mechanical stress. When chromatin is condensed, the nucleus becomes more rigid. When chromatin is decondensed, the nucleus becomes more elastic with less force exerted on the inner nuclear membrane. This ...
Basic units of chromatin structure. In molecular biology, a chromatosome is a result of histone H1 binding to a nucleosome, which contains a histone octamer and DNA. [1] The chromatosome contains 166 base pairs of DNA. 146 base pairs are from the DNA wrapped around the histone core of the nucleosome.
The organization of chromosomes into distinct regions within the nucleus was first proposed in 1885 by Carl Rabl.Later in 1909, with the help of the microscopy technology at the time, Theodor Boveri coined the termed chromosome territories after observing that chromosomes occupy individually distinct nuclear regions. [6]
The nucleosome assembles when DNA wraps around the histone octamer, two H2A-H2B dimers bound to an H3-H4 tetramer. The nucleosome core particle is the most basic form of DNA compaction in eukaryotes. Nucleosomes consist of a histone octamer surrounded by 146 base pairs of DNA wrapped in a superhelical manner. [10]
[1]: 405 During most of the cell cycle these are organized in a DNA-protein complex known as chromatin, and during cell division the chromatin can be seen to form the well-defined chromosomes familiar from a karyotype. A small fraction of the cell's genes are located instead in the mitochondria. [1]: 438 There are two types of chromatin.
The fundamental unit of chromatin, called a nucleosome, contains DNA wound around a protein octamer. This octamer consists of two copies each of four histone proteins: H2A, H2B, H3, and H4. Each one of these proteins has a tail extension, and these tails are the targets of nucleosome modification by methylation.
The nucleosome is the basic unit of DNA condensation and consists of a DNA double helix bound to an octamer of core histones (2 dimers of H2A and H2B, and an H3/H4 tetramer). About 147 base pairs of DNA coil around 1 octamer, and ~20 base pairs are sequestered by the addition of the linker histone (H1), and various length of "linker" DNA (~0 ...