Chromatin remodeling by RNA polymerase II

Tight compaction of eukaryotic DNA in chromatin having several levels of organization results in formation of a structure that is barely accessible to regulatory protein complexes and enzymes such as DNA- and RNA-polymerases. To deal with this intricate chromatin organization, numerous chromatin remodeling mechanisms operating at various levels of chromatin structure have been developed. Recently, it has become apparent that numerous intranuclear processes of DNA metabolism (such as transcription, repair, etc.) are often regulated at the level of chromatin remodeling. The mechanisms of chromatin remodeling and its regulation are beginning to emerge. Thus, the histone octamer has a remarkable ability to survive action of various processive enzymes, such as DNA- and RNA-polymerases, as well as ATP-dependent remodelers. Here, we discuss the mechanisms of chromatin remodeling during transcription with a primary focus on chromatin remodeling by transcribing Pol II.