LINKER HISTONES H1 AND H5 PREVENT THE MOBILITY OF POSITIONED NUCLEOSOMES

We have previously identified a generally occurring short-range mobili ty of nucleosome cores on DNA in relatively low ionic strength conditi ons. Here we report that this mobility of histone octamers positioned on constructs of 5S rDNA is suppressed by the binding of histone H1 or H5 to the nucleosome. Histone H5 is the more potent inhibitor of nucl eosome mobility, in accordance with its higher affinity for chromatin, We propose that this reversible restraint on chromatin dynamics may p lay a role in local regulation of processes that require access to the DNA.