The architecture of transcription elongation

The molecular machines that carry out transcription in all domains of life—bacteria, archaea, and eukaryotes—are multisubunit RNA polymerases ( 1 ). Over the past 15 years, structural analyses at ever higher resolution, in particular hybrid approaches that combine x-ray crystallography and single-particle cryo–electron microscopy, have provided detailed insights into how these enzymes work ( 2 ). On page 921 of this issue, Ehara et al. ( 3 ) apply such a multidisciplinary structural approach and in vitro transcription assays to reveal functional insights into a complete elongation complex from the yeast Komagataella pastoris , encompassing RNA polymerase II (RNAPII) and the transcription elongation factors Elf1, Spt4/5, and TFIIS. The results uncover the detailed molecular mechanisms by which these factors can not only enhance transcription elongation, but also pausing.