Proteins with seven conserved ''helicase domains'' play essential role
s in all aspects of nucleic acid metabolism. Deriving energy from ATP
hydrolysis, helicases alter the structure of DNA, RNA, or DNA:RNA dupl
exes, remodeling chromatin and modulating access to the DNA template b
y the transcriptional machinery. This review focuses on the diverse fu
nctions of these proteins in the process of RNA polymerase II transcri
ption in eukaryotes. Known or putative helicases are required for gene
ral transcription initiation and for transcription-coupled DNA repair,
and may play important roles in elongation, termination, and transcri
pt stability. Recent evidence suggests that helicase-domain-containing
proteins are also involved in complexes that facilitate the activity
of groups of seemingly unrelated genes. BioEssays 20:634-641, 1998. (C
) 1998 John Wiley & Sons, Inc.