Structural basis of transcription by bacterial and eukaryotic RNA polymerases

DNA-dependent RNA polymerase (RNAP) is responsible for cellular gene transcription. Although crystallographic studies on prokaryotic and eukaryotic RNAPs have elucidated the basic RNAP architectures, the structural details of many essential events during transcription initiation, elongation, and termination are still largely unknown. Recent crystallographic studies on a bacterial RNAP and yeast RNAP II have revealed different RNAP structural states from that of the normal transcribing complex, as well as the basis of transcription factor functions, advancing our understanding of transcription. These studies have highlighted unexpected similarities in many fundamental aspects of transcription mechanisms between the bacterial and eukaryotic transcription machineries. Remarkable differences also exist between the bacterial and eukaryotic transcription systems, suggesting directions for future studies.

► Structures of RNA polymerase (RNAP) II backtracked by 1–8 nt residues are revealed. ► TFIIS rescues RNAP II by adjusting the position of RNA for cleavage. ► Gfh1 inhibits bacterial RNAP by blocking NTP intake and changing the RNAP structure. ► The RNAP structural change is potentially involved in translocation and termination. ► The fundamental mechanisms of bacterial and eukaryotic transcription are highlighted.