Both the arginine-rich (F3) and the very lysine-rich (F1) histones form complexes with bacterial (Micrococcus lysodeikticus) RNA polymerase as well as with the DNA template. The lysine-rich histone complex with the enzyme is unstable and dissociates in the presence of DNA, whereas the complex of RNA polymerase with arginine-rich histones is much stronger and dissociates only by increasing the ionic strength of the solution. Certain polyanions can also dissociate the arginine-rich histone complexes with RNA polymerase and thus reverse the inhibition of RNA synthesis maintained by the formation of such complexes. This behavior closely parallels the activation of RNA polymerase in isolated nuclei and chromatin by salts and polyanions. Since no detectable dissociation of DNA-histone complexes was seen at the ionic strengths required for maximum dissociation of the polymerase complexes with arginine-rich histones, it is proposed that the salt activation of RNA polymerase in chromatin may be due to the dissociation of such enzyme-inhibitor complexes present in the nuclei of eucaryotes.
ASJC Scopus subject areas