Navigation Links
Nucleosome


A nucleosome is the fundamental repeating subunit of eukayotic DNA, and is made up of DNA and histone proteins. It is found in the cell nucleus in eukaryotes. All chromatin (except for that packaged in the sperm nucleus) consists of nucleosomes. Nucleosomes can be seen with an electron microscope as bead-like structures along the DNA.

Structure

The histones make up the central core particle of the nucleosome. The DNA is wrapped around this protein complex in two turns, with each turn consisting of about 80 base pairs. Together with the DNA linking two nucleosomes, there are about 200 bps of DNA per nucleosome.

Nucleosomes are involved in processes ranging from compaction of DNA to transcriptional control, and appear to be major carriers of epigenetically inherited information as well. Repeating nucleosomes with intervening "linker" DNA form the 10-nm-fiber, known descriptively as "beads on a string", and have a packing ratio of ~6, compared to "free" DNA (per nm length). A chain of nucleosomes can be arranged in a 30-nm-fiber, a compacted structure (once thought to be a helical solenoid, but now considered likely to exist as a zig-zag structure in vivo) with a packing ratio of ~40. The H1 histone stabilizes this structure. Beyond 30 nm fiber the structure of chromatin is poorly understood, but it is classically suggested that the 30 nm fiber is arranged into loops along a central protein scaffold to form transcriptionally active euchromatin. Further compaction leads to transcriptionally inactive heterochromatin.


'"/>


(Date:7/10/2014)... 8, 2014 Fingerprint Cards, ... design win (DW). An Asian OEM has selected FPC1021 for ... start in August 2014.   FPC is proud ... has a planned date for start of mass production in ... of SEK 5M, for delivery in the first half of ...
(Date:7/10/2014)... the large, mainly tropical flowering plant family Melastomataceae (Meadow Beauty ... rely on bees for their pollination. Only about 100 are ... flowers of Axinaea appear in clusters of few ... different species are pink, yellow, orange or red. The stamens ... of their bulbous appendages. The pollination mechanism of Axinaea ...
(Date:7/10/2014)... your popcorn or soap might not be ape friendly, and ... an analysis in the Cell Press journal Current Biology ... oil has already led to the conversion of Southeast Asian ... particular. If guidelines are not put in place very soon, ... Asia into Africa will be bad news for great apes ...
Breaking Biology News(10 mins):FPC Wins DW and Initial Ramp Order for FPC1021 Touch Sensor for Flagship Smartphone from Asian OEM 2Novel type of bird pollination mechanism discovered in South America 2Hunger for vegetable oil means trouble for Africa's great apes 2
... than a dozen countries joined together to sequence the tomato ... The Tomato Genomics Consortium directed the research effort, which ... Foundation and the USDA,s Agriculture Research Services. The OU ... Emeritus in the College of Arts and Sciences, was one ...
... 2012) -- A detailed analysis of more than 4 ... help electricity producers slash as much as 30 percent ... dioxide from power plant emissions. The research by ... Lawrence Berkeley National Laboratory (LBNL) and the Electric Power ...
... Madrid, May, 31st, 2012.- Madrid will become ... during the Biomedical Innovation Conference 2012, focused on ... Madrid-MIT M+Vision Consortium. This new organization has been ... and the regional Government of the Comunidad de ...
Cached Biology News:New materials could slash energy costs for CO2 capture 2New materials could slash energy costs for CO2 capture 3MADRID-MIT M+Vision Consortium hosts Biomedical Innovation Conference 2012 2
Other biology definitionOther Tags