Lariat lessons

摘要

One of the seminal discoveries that propelled biologists towards an increased appreciation of RNA's many roles in cellular function was that genes can be interspersed with non-protein-coding sequences called introns. During the transcription of genomic DNA into messenger RNA, the RNA sequences generated from introns are removed by the spliceosome (a complex enzyme formed from proteins and RNA), the structure of which is poorly understood. On page 193 of this issue, Robart et al. provide insight into the mechanism of this splicing process by reporting the crystal structure of a self-splicing group Ⅱ intron - an RNA enzyme that shares a common ancestor with spliceosomal RNAs.