Functional studies on chromatin.

Abstract

ABSTRACT Functional studies on chromatin include assays of template activity and template capacity. Template activity is the measure of the rate of polynucleotide synthesis supported by a chromatin template in an incubation mixture including exogenous DNA-dependent RNA polymerase. It can be a highly misleading criterion unless great care is taken to standardise conditions. Template capacity is the measure of the DNA in a preparation of chromatin as compared with purified DNA, which is accessible to transcription by exogenous DNA-dependent RNA polymerase. It is determined by studying the complexity of the RNA made in the reaction, usually by RNA-DNA hybridization. The effects of different methods of preparation of chromatin, different RNA polymerases, conditions of incubation and purification of RNA are discussed. The application of these and other methods to the study of reconstituted chromatin is described.