PRESS RELEASE
LINKER HISTONES DO NOT PACKAGE RANDOMLY

RESEARCHERS FROM THE CRG DEMONSTRATE THAT LINKER HISTONES HAVE A SPECIFIC FUNCTION IN THE PACKAGING OF DNA IN CHROMATIN

Researchers from the Centre for Genomic Regulation have discovered that linker histones have a definite role in the compaction of DNA in chromatin for the formation of chromosomes.

The work, coordinated by Miguel Beato and a result of the collaboration between researchers from Germany, New Zealand and Spain, will be published on the 1st of October in the prestigious scientific journal PLoS ONE.
DNA is found compacted in chromatin for the formation of chromosomes and histones are the molecules responsible for this compaction. Various types of histones are recognized and they are classified as core histones or linker histones.
To date, all the subtypes of linker histones had been considered to be primordial elements for the compaction of DNA in chromatin but they had not been observed to have specific functions.
The work lead by Miguel Beato is a continuation of previously published findings, also by researchers from the CRG (M. Sancho et al. PLoS Genetics 4, e100227), which observed that, in breast cancer cells, the subtypes of linker histones have different functions. The work, which will be published on Thursday in PLoS ONE, reveals the specific roles of the subtypes of linker histones that can have different affinities with chromatin and a greater or lesser compaction capacity.
Moreover, contrary to the currently accepted idea, the study shows that these histones do not impede the function of ATP-dependent chromatin remodelers in chromatin reorganization.
This discovery provides new clues about the condensation mechanisms of DNA in chromatin and demonstrates how the subtypes of linker histones can be classified as: weak, intermediate or strong condensers. At the same time the door is opened to new studies into the understanding of mechanisms for the conservation and organization of the genome in the nucleus. The genome is the code which determines the biological characteristics of living things. The linear sequence of the DNA in our chromosomes is more than 2 meters long. In order to put all of this information into the tiny nucleus of a cell, it is necessary to package it extremely efficiently.
For this study, the researchers used nucleosomes assembled with recombinant histones and minichromosomes which were analyzed using both biochemical methods and an atomic force microscope.
Glossary:
CROMATIN: Genetic material of the nucleus formed by very long molecules of DNA associated with other substances, principally histones, and which also contain proteins, RNA, enzymes, ions, etc.
NUCLEOSOME: Spherical structure of the chromatin fiber of eukaryotic cells, which contains eight histone molecules and approximately two hundred DNA base pairs.
Reference: Jaime Clausell, Nicole Happel, Tracy K. Hale, Detlef Doenecke and Miguel Beato. (2009) “Histone H1 Subtypes Differentially Modulate Chromatine Condensation without Prneventing ATP-dependent Remodelling by SWI/SNF or NURF”. PLoS ONE. DOI: 10.1371/journal.pone.0007243
For further information: Laia Cendrós, Dpt. Comunicació i RRPP, Centre de Regulació Genòmica (CRG), Dr. Aiguader, 88 – Edif. PRBB, 08003 Barcelona. Tel. +34 93 316 02 37