Roles of DNA Topoisomerases in Transcription

This chapter discusses role of DNA topoisomerases in transcription initiation in the context of DNA supercoiling. The chapter focuses on one specific role of topoisomerases in transcription elongation. Transcription elongation is probably one of the most frequent genetic events. A number of studies have suggested that transcription elongation has a direct impact on both DNA structure and function. The roles of topoisomerases in regulating transcription elongation are discussed. Topoisomerases modulate the impact of transcription elongation on DNA structure and function. Topoisomerases have evolved to solve the topological problems arising from various genetic processes on double-helical DNA. While DNA topoisomerases are essential for DNA replication due to the topological intertwining of the parental DNA, the roles of DNA topoisomerases in transcription are much less clear. However, increasing evidence indicates that topoisomerases may be involved in modulating supercoiling generated during transcription elongation. Because supercoiling of DNA is an important property of DNA and affects almost every aspect of DNA function, the roles of topoisomerases in transcription are expectedly complex. It will not be possible to completely understand DNA function without having a complete knowledge of the roles of topoisomerases. Additional research efforts are needed in this area.