In vivo methods to analyze chromatin structure

A groundswell of interest in chromatin structure and its role in regulating the function of DNA in transcription, replication, recombination and repai r has developed in the past decade. Fueled by genetic observations of effec ts of histone mutations on transcription and identification of genes whose products must alter chromatin structure as they affect gene activity, this subject leapt to the forefront in the past two years with the correlation o f certain transcription factors with enzymes that post-translationally modi fy histones and are presumed to alter chromatin structure thereby. Surprisi ngly few experimental reports have actually addressed chromatin structure. In part, this may be related to the technical difficulties of traditional a pproaches to structure inference. Methods have become available recently fo r assessment of various aspects of chromatin structure in vivo. Study in in tact cells may limit potential problems resulting from loss of components o r rearrangement of structures and simplify analysis by eliminating the need for isolation of organelles.