[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 were 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 primary focus on chromatin remodeling by transcribing Pol II.