Toward structural understanding of eukaryotic transcription elongation.

Transcription is an essential biological process that underlies all cellular and organismal activities. In eukaryotes, RNA polymerase II (RNAPII) transcribes every protein-coding gene and many non-coding genes, playing a central role in gene expression. Transcription generally occurs in three steps: RNAPII initiates transcription from a gene promoter, elongates RNA as it traverses the gene body, and terminates transcription at the end of the gene. Dynamic interactions with multiple accessory factors allow RNAPII to form functional transcription complexes and accomplish these processes in chromatin. Recent progress in structural biology has illuminated the structural and mechanistic details of RNAPII functions, particularly promoter-proximal pausing, nucleosome transcription, and transcription termination. This review provides a survey of these advances and discusses future directions.