SNAP output for PDB entry 8h0v [SNAP web server]

PDB-id

8h0v; SNAP-derived features in text and JSON formats; DNAproDB

Class

transcription

Method

cryo-EM (3.8 Å)

Summary

RNA polymerase ii transcribing a chromatosome (type i)

Reference

Hirano R, Ehara H, Kujirai T, Uejima T, Takizawa Y, Sekine SI, Kurumizaka H (2022): "Structural basis of RNA polymerase II transcription on the chromatosome containing linker histone H1." Nat Commun, 13, 7287. doi: 10.1038/s41467-022-35003-z.

Abstract

In chromatin, linker histone H1 binds to nucleosomes, forming chromatosomes, and changes the transcription status. However, the mechanism by which RNA polymerase II (RNAPII) transcribes the DNA in the chromatosome has remained enigmatic. Here we report the cryo-electron microscopy (cryo-EM) structures of transcribing RNAPII-chromatosome complexes (forms I and II), in which RNAPII is paused at the entry linker DNA region of the chromatosome due to H1 binding. In the form I complex, the H1 bound to the nucleosome restricts the linker DNA orientation, and the exit linker DNA is captured by the RNAPII DNA binding cleft. In the form II complex, the RNAPII progresses a few bases ahead by releasing the exit linker DNA from the RNAPII cleft, and directly clashes with the H1 bound to the nucleosome. The transcription elongation factor Spt4/5 masks the RNAPII DNA binding region, and drastically reduces the H1-mediated RNAPII pausing.