Su et al. (2024). Molecular Cell. doi: 10.1016/j.molcel.2024.01.023
…rus strains Escherichia coli DH5-alpha New England Biolabs C2987 Escherichia coli BL21 (DE3) RIL Merck 230280 Escherichia coli DH10EMBacY Geneva Biotech N/A Biological samples Porcine thymus tissue Pel-Freez Biologicals 59451-2 Chemicals, peptides, and recombinant proteins RNA Polymerase II Vos et al., 201840 N/A SPT4 (DSIF) Bernecky et al., 201762 N/A SPT5 (DSIF) Bernecky et al., 201762 N/A NELF-A (NELF) Vos et…
Pel-Freez products cited: Pig Thymus (59451)
Abstract
Metazoan gene expression regulation involves pausing of RNA polymerase (Pol II) in the promoter-proximal region of genes and is stabilized by DSIF and NELF. Upon depletion of elongation factors, NELF appears to accompany elongating Pol II past pause sites; however, prior work indicates that NELF prevents Pol II elongation. Here, we report cryoelectron microscopy structures of Pol II-DSIF-NELF complexes with NELF in two distinct conformations corresponding to paused and poised states. The paused NELF state supports Pol II stalling, whereas the poised NELF state enables transcription elongation as it does not support a tilted RNA-DNA hybrid. Further, the poised NELF state can accommodate TFIIS binding to Pol II, allowing for Pol II reactivation at paused or backtracking sites. Finally, we observe that the NELF-A tentacle interacts with the RPB2 protrusion and is necessary for pausing. Our results define how NELF can support pausing, reactivation, and elongation by Pol II.