Chengjin Zhu

Coupling transcription and translation In bacteria, the rate of transcription of messenger RNA (mRNA) by RNA polymerase (RNAP) is coordinated with the rate of translation by the first ribosome behind RNAP on the mRNA. Two groups now present cryo–electron microscopy structures that show how two transcription elongation factors, NusG and NusA, participate in this coupling. Webster et al. found that NusG forms a bridge between RNAP and the ribosome when they are separated by mRNA.

Abstract Prokaryotic messenger RNAs (mRNAs) are translated as they are transcribed. The pioneering ribosome potentially contacts RNA polymerase (RNAP), forming a supramolecular complex known as the expressome. The basis of expressome assembly and its consequences for transcription and translation are poorly understood. Here we present a series of structures representing uncoupled, coupled and collided expressome states determined by electron cryomicroscopy.